"The most difficult way of reaching the World Cup finals is via the South American group," says Ecuador captain Antonio Valencia. "You can play in Barranquilla in the north of Colombia by the Caribbean Sea, where it's 40 degrees and humid. In La Paz in Bolivia, it's close to 4,000 metres altitude. It takes two or three days to prepare for a game there and then two or three days for your body to recover. It's really difficult and that's from an Ecuadorian who is used to playing at nearly 3,000 metres in Quito."
Over the next week, the national sides of 10 South American countries will play the last two of 18 qualifying matches, bringing to a conclusion a campaign that began in October 2015.
What makes CONMEBOL qualifying so difficult? Well, it features some of the best players in the world -- Lionel Messi, Neymar, Radamel Falcao and Luis Suarez among others -- as well as six of the top 16 ranked teams: Brazil (second), Argentina (fourth), Chile (ninth), Colombia (10th), Peru (12th) and Uruguay (16th). And then there are the logistical issues associated with travel and playing at altitude or in searing heat or humidity.
"I look at the other (regions) and see weaker teams where you are almost certain that one of the sides will win, where you see really high scoring and one-sided matches," says former Uruguay captain Diego Forlan. "There are no 6-0 and 7-0 score lines in South America."
The all-against-all qualification format has existed in South America since 1996 and competition is fierce; even at this late stage only runaway leaders Brazil have confirmed their passage to Russia next year.
Three other teams will join the Selecao and just seven points separate second-placed Uruguay from Ecuador, in eighth. Messi's Argentina are fifth, outside the automatic spots, while Chile, winners of the last two Copa America tournaments, are sixth.
Meanwhile whoever finishes fifth will face a two-game playoff vs. New Zealand in November. The All Whites are 113th in the world, some 45 places below the lowest-ranked South American team, 68th-place Venezuela.
They are the only CONMEBOL team never to have reached a World Cup and, along with Bolivia -- ranked 46th, ahead of Australia, South Korea, Greece, Ivory Coast and Ghana -- are one of only two nations to have no chance of qualification going into the final two games.
There are rivalries everywhere, ones that transcend sport and reflecting long-standing historical enmities between countries. With competition so fierce, little wonder that the South American group features more yellow cards -- 4.6 per match -- than anywhere else in the world.
Great drama it might be, but should it be like this? Valencia says "I don't think it's fair that only four teams qualify automatically," while former Venezuela international and current ESPN analyst Alejandro Moreno argues it does not compare favourably to the system in other regions. CONCACAF, the North, Central American and Caribbean confederation, for example, gets three automatic spots.
"It's not the same to go and play against Brazil, Argentina, Uruguay, Colombia, Ecuador, Paraguay or Chile as it is to go to some of the teams in CONCACAF," says Moreno. "I look at some of those teams and think 'it doesn't seem right, it doesn't feel right.' But that's how it is. If you qualify from the South American group then you know that you've done it against the highest quality of competition from any group. It's very challenging for everyone and, when you play for a country like Venezuela as I did, you not only have to be at your very best all the time, you also have to hope that the other teams have an off night to get the results to give you an opportunity to fight for a World Cup spot."
Other teams in other regions must travel substantial distances, face logistical difficulties and play quality opponents in exacting conditions, but none face such challenges as often as those involved in South American qualifying.
The playing conditions
On Wednesday morning, the Brazilian squad will train near Rio de Janeiro, then fly four hours to Santa Cruz de la Sierra, Bolivia's second city, which is located near the countries' border and sits at an elevation of 416 metres above sea level. But Bolivia vs. Brazil, scheduled for the following day, is not being played in Santa Cruz.
"They will sleep for six hours and then, six hours before the game, will take a flight into the Andes to La Paz," says Sergio Rangel, a journalist who follows Brazil for the respected Folha de Sao Paulo paper. "It's crazy. The game will start at 3 p.m. when people are still working, then the team will return to Brazil on the same day after the match. The longer they stay, the worse the altitude will be for the players. It's not ideal, but the doctors have told them it's the best thing to do."
CONMEBOL games are regularly played at altitude in La Paz, which is 3,600m above sea level, and in the Ecuadorian capital, Quito.
"It's hard to play in Quito at 2,800 metres," says Forlan. "The ball moves faster because the air is thinner. It's not like La Paz in Bolivia where you struggle for air after every run, but there's a difference which upsets your timing and reactions, your co-ordination. So it's a different type of football; slower, more patient."
In terms of home-field advantage, consider that Bolivia have won four of their eight home games in 2018 World Cup qualifying, but have lost eight straight times away from home, scoring two and conceding 22. Chile lost there last month, as did Argentina in March.
"It's difficult even when you sit on the bench in La Paz," says Argentina defender Marcos Rojo. "My second [game there] was this year when I played for 90 minutes and we lost 2-0. That was a very bad result for us and means we have to win our final games to make sure we go to Russia."
In 2007, FIFA banned international matches from being played at more than 2,500m above sea level but the suspension would last less than a year. On April 1, 2009, an Argentina team featuring the likes of Messi, Carlos Tevez and Javier Mascherano -- and coached by Diego Maradona -- was beaten 6-1 in La Paz.
Moreno explains that Venezuela players were told to use a hyperbaric chamber for six weeks leading into a visit, but adds that club football made proper preparation difficult: "Barca are not going to release Messi for six weeks," he jokes.
"And when you show up in Bolivia, the first thing you see in the locker room is oxygen canisters. It becomes not only a physical challenge, but a mental one. You do a couple of sprints when you arrive and your lungs are burning and you think: 'Hang on; I thought I was prepared for this.' You're also under pressure as the game is imminent, so you have to trust your body to push forward because you have a chance of reaching the World Cup finals. We won 1-0 (in 2009), but Bolivia did hit the post three times."
But one team's disadvantage is another's advantage and that extends throughout the region.
"We used the Venezuelan heat to help us," says Moreno. "We knew Uruguay or Argentina were coming from the cold, so we'd press them all over hoping that they would run out of gas. Teams like Venezuela grab onto something like that and try to close the talent gap and take advantage of the fact that our opponents don't want to be there, that they're uncomfortable."
Meanwhile, says Colombia full-back Santiago Arias: "The air is heavier in the north, the sun stronger. Barranquilla is tough for opponents; they don't like coming to play us there."
"I played in Barranquilla three days after playing 90 minutes against Brazil," says Rojo of a game in November 2015. "It wasn't the temperature, but the humidity. It was 93 percent. We won 1-0. Sometimes having more world-class players than your opponents can make the difference."
"I've seen a couple of [European] managers complain about four-hour flights to Russia or Ukraine, but four hours is nothing to me," says Forlan with a laugh. "I've played international games two days after travelling around the world. Those first transatlantic journeys from Manchester back to Uruguay were a shock. I'd leave an English winter and arrive in the heat of the South American summer. But that was only to meet up with my teammates. We would then travel on from Montevideo to countries in the north of South America like Colombia or Venezuela. Montevideo to Bogota or Quito is seven hours and we always had to change in Sao Paulo or Panama or somewhere else.
"We wouldn't be flying in luxury, either," he continues. "Uruguay's players flew in economy when I started, though I soon started to pay the extra for business or first class from my own pocket. It made a big difference and I could get some sleep, especially as I could be taking four or five flights just to reach a Uruguay game in South America. Returning to Europe can also be tiring. You might get back late on Thursday night and have to be training on Friday for a game on Saturday. You could have picked up a knock or be a bit down because you didn't play well or your team lost."
In recent years, rich European clubs have chartered planes to get their stars back as quickly as possible: "If Argentina have six or seven players in Spain, for example, then it makes sense for them to fly privately together, even if they play for rival clubs," says Forlan.
"A lot of the games are not played in the capital cities," says Moreno. "Travel in South America is not like it is in first-world locations. It takes a toll on players, If they're not prepared to make that transition and go into stadiums where they might be no hot water, it can impact on performance."
Watching football in South America means loud, passionate atmospheres, tinged with a hint of lawlessness that can intimidate opponents. Matches are staged in some of the most iconic venues in world football; Brazil spread their games around venues that were rebuilt for the 2014 World Cup finals, though the famous Maracana in Rio hasn't been used during these qualifiers because of a row with the stadium's owners.
Meanwhile, Argentina also spread their games around but they play more than anywhere else at River Plate's El Monumental, at which they won the 1978 World Cup final amid a sea of ticker-tape. However, it is the home of River's great rivals that will stage Thursday's vital game against Peru.
Claudio Tapia, the Argentinean FA president and a Boca Juniors season-ticket holder, decided La Bombonera -- "the chocolate box" -- would be the venue because the stadium is famous for its intimidating atmosphere. Tapia has sound reasoning, yet history provides a warning: In 1969, Argentina played Peru needing a win to qualify. The match was switched to La Bombonera for similar, atmosphere-related reasons: Argentina drew 2-2 and did not go to Mexico 1970.
The vast bowl of Montevideo's Estadio Centenario, which staged the 1930 World Cup final, hosts all Uruguay's home qualifiers. Its rebuilding is planned as part of a joint bid with Argentina to host the 2030 World Cup but, for now, the main stand holds archaic wooden benches with poor sight lines. The wind can howl in off the River Plate in winter and yet, despite all that, it becomes a seething cauldron when Uruguay have a big game.
"The Centenario is the most difficult place to play," says Colombia's Arias. "It's the crowd, but also the Uruguay team is always strong, always very strong."
"My fondest memory is beating the fully-loaded Argentina team 1-0," says Moreno of a qualifier in October 2011. "The streets were full of fans, surrounding the bus. It allowed the fans to dream that there was a possibility that we could get into the World Cup. The high emotion our fans generated worked for us and against Argentina."
"Fans threw eggs at our bus on the way to training," says Forlan of a trip to Peru in 2013, when the hosts hoped to reach their first World Cup since 1982. "They were outside our hotel singing in the night, too. We expected that. We won 2-1. You really feel like you've achieved something when you win a game like that."
Moreover, Forlan adds that the environments teams face in qualifying can prepare them for the World Cup itself, citing the 2010 tournament in South Africa as an example.
We played a quarter final against Ghana in Soweto and 80,000 people wanted us to lose. But because we were used to that adversity, those really tough games, we were used to that 'us against the world mentality' from the every group game. Eggs, songs, opponents. I love the South American group. There's not a single easy game."
There's a joke that, in order to win the World Cup, a South American country must avoid a smooth qualification. One of the reasons why future champions so often struggle in the preliminary stage is due to the rivalries that have built among nations that meet so often.
"In 1985, Argentina scored 10 minutes from time against Peru to equalize and qualify for the World Cup," says Brazilian journalist Alex Sabino, who has travelled extensively around Argentina to write about football. "The scorer was Ricardo Gareca, Peru's manager nowadays."
After scraping through, Maradona-inspired Argentina went on to become world champions in 1986. Something similar occurred seven years later when, with teams split into two groups of five, Brazil began their last match, against Uruguay at the Maracana, lying outside the three automatic qualification spots.
Romario was called back from exile and played the game of his life, scoring twice as Brazil won 2-0. Earlier in the same cycle, a huge shock was caused when Bolivia beat Brazil in La Paz. Fans wanted to see coach Carlos Alberto Parreira fired but he kept his job and ultimately won the World Cup in the United States.
Brazil, as the most successful nation in World Cup history, are seen as the team to beat by every opponent, no matter how big or small.
"When you play for Argentina in an important game against Brazil it's one of the greatest feelings that a player can have," says Rojo. "It's a game that could easily be the World Cup final, except it's only a qualifier for the World Cup finals. I'll never forget playing against Brazil in Buenos Aires for the qualifier for the Russia World Cup (in 2015)."
"The Brazil against Argentina rivalry grew from geography because we could hardly play against England or France in the 1920s," says Rangel. "It's the greatest rivalry in South America, between two contrasting styles. Brazilian is joga bonito, the beautiful football. Argentinian is more physical.
"Uruguay is also a big rival for Brazil. We can't forget what happened in 1950 (when Uruguay won the World Cup with a 2-1 win in Rio). I was at the game in Montevideo when Brazil won 4-1 this year and there was so much satisfaction among the players, for the historical aspect and also because Uruguay have great players like Suarez and [Edinson] Cavani."
Every team has rivalries.
"All of Colombia's neighbours want to beat us, which is normal, but they want to beat us more now because we're seen as one of the best teams," says Arias. "We have players who everyone has heard of around the world: Radamel [Falcao], James [Rodriguez] and Juan [Cuadrado]. We're in a good moment for Colombian football, which makes it another stronger team for the group. It also makes things very complicated for us, but it's something we have to overcome and we're been doing well."
Beyond football, meanwhile, the rivalries are given an edge by the state in which many nations find themselves.
"A lot of our countries in South America and, in particular, Venezuela right now, go through political, social and financial turmoil and economic instability," says Moreno. "They have a way of showing on the field which is beyond the power of the player and which is something people outside South American might not appreciate. The national team game for each of these countries is a period in which all of those problems are forgotten and this becomes one thing to grab hold of and allow you to dream big dreams and think big thoughts. The whole country leans on their teams to give them a degree of happiness and joy. The players feel that emotion. If you can deliver that moment of joy, you'll never be forgotten. It's far more than three points."
"There are 10 very strong teams and every single one of those countries starts the group by thinking they have a realistic chance to qualify for the finals," says Arias. "That doesn't happen in other parts of the world where there are much weaker teams.
At least half of the South American teams won't be going to Russia next year but not qualifying doesn't equal a waste of time. With the standard of play so high, interest remains throughout and it is possible to build for the future.
"The strength of the CONMEBOL group has helped countries like Venezuela close the gap," says Moreno. "That makes the group even more intriguing. Venezuela can go to Argentina and get a 1-1 draw as they did recently. It's not a freak result either. Everyone has become more competitive and countries have learned to maximise their talent. Argentina or Brazil has a much bigger talent pool than Venezuela, so it was up to us to use what we have well."
Ecuador, meanwhile, had only won five qualifying games before 1996 but, since making their first World Cup in 2002, have qualified two further times. South American nations are honed by such a tough path to the finals that they're ready when they start; in the last World Cup, only Ecuador failed to make it out of the group stage.
"We're a county of three million people, yet we reached the semifinals of the 2010 World Cup," says Forlan. "Three million is half the population of Scotland. Uruguay are very, very proud of our achievements as a national team. But what helps us prepare apart from players, spirit and a manager? Playing some of the best teams in qualifying. We finished fifth in the 2010 qualifiers and had to beat Costa Rica to reach the finals."
With the exception of qualifying for the 2006 World Cup, when Uruguay lost to Australia, South American teams have dominated recent intercontinental playoffs -- Uruguay knocked out Costa Rica and Jordan in 2009 and 2013 respectively -- and whoever finishes fifth this year will be expected to beat Oceania representatives New Zealand.
"It used to be only the biggest South American players from the best countries in Europe," says Forlan. "Now, every national team will have players at the top level in European leagues. They improve; those in Spain become used to playing against Messi so they're not frightened of him. They get used to better training facilities, pitches, preparations and logistics so when they come home they demand improvements there. That raises standards further."
"Four or five [to qualify] is enough teams", says Rangel. "The CONMEBOL group works because it's so competitive. Seven from 10 countries going to a World Cup finals is too much."
Given the strength of his own country -- Brazil is the only team to have played in every World Cup -- Rangel might be predisposed to hold such a view, but it is one supported by others from South America.
"When I hear of FIFA expanding the World Cup finals to give countries like Venezuela a chance (48 teams will qualify from 2026, including six from South America), perhaps I'm in the minority because I don't think it's a good idea," says Moreno. "The World Cup finals are supposed to be the elite of the elite. It's an exclusive tournament and expanding it would dilute the significance. If we have to continue raising our standards and nurturing talent, continue going to the toughest places, then so be it. We've come a long way, we're no longer an easy three points and I'm proud of that. We matter, we can get results and the next generation can improve and reach the finals."
"When Colombia reached the World Cup in 2014, it was the first time since 1998 and thousands of fans went," says Arias. "Some even drove; it took them two days across the Amazon. I was substitute for our first game in the World Cup finals against Greece in Belo Horizonte. I was watching the Colombian fans, maybe 25,000 of them, as much as the game. It made me so proud. And then I came on the pitch. We won, it was a wonderful occasion."
"We were close to reaching the 2010 World Cup finals in my time and had two games left but we lost at home to Paraguay," says Moreno. "We have to live with that and what made it more disappointing was that we tied with Brazil in the last game. Uruguay jumped over us into the playoff position."
That Uruguay team, which was only fifth-best in South America, ended up fourth in the world. Just in case you were still wondering how tough CONMEBOL qualifying can be.