Fifty years ago, the man we now know as Muhammad Ali knocked out Sonny Liston to become, at 22, one of the youngest heavyweight boxing champions of all time. Photographer Danny Lyon spent three days with Ali in 1970 and shares some of his best photos and what he remembers about the champ.

People from all over the world visit Norway every year to compete in an annual bicycle race 540 kilometers (336 miles) long. It is punishing on the body. Especially the feet, which Espen Rasmussen took photos of minutes after people crossed the finish line.

When the Super Bowl kicks off Sunday in New Jersey, photographer John Biever will be there. Just as he has for all of the 47 other Super Bowls. Biever is one of four photographers who have been on the field for every championship game since 1967.

Jan Sochor, a 39-year-old photographer from the Czech Republic, discovered that wheelchair rugby is more than sport for players in Colombia. It is a way for disabled men in the South American country to show how strong they are physically and mentally.

Every June, people gather in Florence, Italy, to attend a few soccer matches. But this is no ordinary soccer. Florentine soccer, which has been a tradition for hundreds of years, allows players to fight their opponents. German photographer Michael Lowa captured this unique sport in his project “The Last Gladiators.”

Welcome to Thunderdome, where winners and losers can be as young as age 5. It's called kids' MMA, or Mixed Martial Arts, and New York-based photographer Sebastian Montalvo pulls back the curtain on one of the nation's fastest growing youth sports, which claims more than 3 million boys and girls.

Jared Soares went looking for “a piece of community in a big place.” He found it in Barry Farm, one of the oldest African-American neighborhoods in the nation’s capital, and the Goodman League, a summer basketball organization that’s one of the neighborhood’s premier attractions.

A woman in a Confederate flag minidress. A little boy with an “88” softly shaved into his head. These are some of the faces seen at Bristol Motor Speedway, where NASCAR hosts two of their premier Sprint Cup races each year. This is also the place photographer Tammy Mercure likes to ply her trade.