Go on, enjoy those warm rays today because, back in 1978, former President Jimmy Carter declared May 3 National Sun Day. Studies have shown that 20-30 minutes of natural sunlight at least three times a week will do wonders for your physical and mental health. And, we’re not alone basking in the sun. There are several sports stadiums in the United States that are run in part by solar power. Lincoln Financial Field in Philadelphia leads the way. It is the first American stadium with the capability to generate all of its own electricity, thanks in part to more than 11,000 solar panels. In a single day, they can churn out enough kilowatt hours to power two average homes for a year.