History. You can't buy it, but what is it actually worth anyway?
There will be two answers to that question at Anfield on Wednesday when Liverpool face Manchester City in the first leg of their all-Premier League Champions League quarterfinal.
Put it to a Liverpudlian and it would be akin to asking a poet to reel off his favourite poem. There will be recollections of the heroics of former greats -- Kevin Keegan, Kenny Dalglish, Steven Gerrard -- tales of glory in Rome, London, Paris and Istanbul, of Luis Garcia's "ghost" goal against Jose Mourinho's Chelsea, and countless memories of the five times that Liverpool were crowned champions of Europe.
Ask a City supporter and they will tell you that their club is now making history rather than wallowing in it. They have enjoyed taunting neighbours Manchester United about "living in the past" and, with Pep Guardiola's team on the brink of clinching the club's third Premier League title in six years, can rightly claim to be in the midst of their own historic period.
Yet as abstract as it may be in a football sense, history does matter in the Champions League.
You can't buy it, touch it or devise a tactical plan to nullify it, but when Guardiola's men stride onto the pitch at Anfield, and in the return leg at the Etihad next Tuesday, their toughest opponent might be history and the sheer weight of it against them.
A ball has not yet been kicked, but Liverpool vs. Manchester City is already a classic encounter between history and ambition.
It is the old guard against the new wave; empire against uprising. But City are not the first club to find themselves in the position of being wealthy outsiders attempting to gatecrash the elite.
Since the turn of the century, Roman Abramovich at Chelsea, Qatar Sports Investments at Paris Saint-Germain and Abu Dhabi's Sheikh Mansour bin Zayed al Nahyan at City have all combined to transform football with their mammoth financial investments.
But despite their petrodollar spending, they have just one Champions League success between them: Chelsea's penalty shootout victory against Bayern Munich in 2012.
City, Chelsea and PSG have amassed 34 Champions League campaigns between them -- the vast majority since being bought by financially-powerful owners -- but PSG and City have yet to go beyond the semifinal stages. Since Abramovich arrived at Chelsea in 2003, the club have reached two finals, winning one.
Indeed, the Champions League is such a closed shop that there has been only one first-time winner this century: Chelsea. But is that down to history or a reflection of historical dominance?
If we take the 1999-2000 campaign as the first of the 21st Century, there have been 18 Champions League winners and the roll-call is a long list of Europe's most historic clubs.
Real Madrid have won five this century; Barcelona four; Bayern Munich and AC Milan have two apiece; Porto, Liverpool, United and Inter Milan -- all previous winners -- have won one since 2000, with Chelsea the only first-timers in that period. Valencia (twice), Bayer Leverkusen, Monaco, Arsenal, Chelsea and Atletico (twice) have all lost in finals this century as they attempted to win their first European Cup.
Considering that Chelsea, City and PSG have spent close to £3 billion between them over the past 15 years, it goes to show that old, accumulated wealth and history is still able to resist the power of new money.
But is there an intangible factor that makes it so much more difficult for the emerging clubs to succeed in the Champions League? Does the weight of history act as a crucial inspiration rather than a suffocating burden?
Ask Diego Simeone and Atletico Madrid. Twice now, they have lost out to Real in the Champions League final -- the first time when the trophy seemed to be in the bag until Sergio Ramos scored a 93rd minute equaliser for Real.
The super clubs, the historical giants, always seem to deliver when faced with a historically less-successful opponent. Perhaps it is the ghosts of the past, the images of predecessors lifting the European Cup aloft, which gives their players crucial, additional inspiration when it is needed the most.
In contrast, the likes of Atletico Madrid, the PSG and Manchester City have nothing but the pressure of expectation, rather than the reassurance of a path well taken, when the heat is on.
Chelsea overcame their own lack of Champions League history to win in 2012, but by that stage they had been knocking on the door for so long -- and had gone close more times than Abramovich would care to remember -- that perhaps their time had come.
We will find out if City are at that stage yet. If they can use their own recent history to build upon or if the likes of Liverpool (plus Bayern, Real, Barca and Juventus if they get that far) possess that historical edge?
Chelsea had made it to six Champions League semifinals and one final before eventually getting their hands on the trophy in 2012, but City have made to the last four on just one occasion.
In the Champions League, they remain novices, fighting against the streetwise, old-school operators. They may have the best team, but City and Guardiola must still find a way to change the course of history.