Auction of legendary boxer Muhammad Ali's fighting outfit

The boxer shorts worn by legendary boxer Muhammad Ali in the historic "Thrilla in Manila" fight held in the Philippines nearly five decades ago are being sold at Sotheby's in New York.

This event shows that the market for sports memorabilia is growing and attracting the attention of auction houses.

Bids have been pouring in since late March, including a bid of $3.8 million for a pair of Everlast shorts, black and white with Ali's signature.

The auction is expected to be open until April 12. Sotheby's estimates that the famous shorts could fetch between $4 million and $6 million.

In the "Thrilla in Manila" match in October 1975, Muhammad Ali faced Joe Frazier.

The two "old rivals" fought a total of 14 rounds, before Joe Frazier's trainer Eddi Futch threw in the towel. Ali was then announced the winner by the referee.

Notably, the match took place under extremely harsh, hot and stuffy conditions due to the lighting causing the temperature to reach nearly 50 degrees Celsius.

Both Ali and Joe Frazier were affected by the fight, Joe suffered vision problems for the rest of his life and retired early, while Ali also retired in 1981 and was diagnosed with Parkinson's disease just three years later.

Ali passed away on June 3, 2016 at the age of 74, after more than 30 years of battling the disease.

Muhammad Ali, born January 17, 1942 in Louisville, Kentucky, is known as "the greatest athlete of the 20th century."

His achievements were recorded after classic matches that went down in world boxing history.

He was a three-time heavyweight boxing champion and an Olympic gold medalist in the light heavyweight division. He was also known for his efforts to fight for African-American civil rights.