1974: American boxer Muhammad Ali, formerly Cassius Clay, strikes an aggressive pose at a press conference on November 29, 1974. (Photo by Harry Dempster/Express/Getty Images); American actor Will Smith at the Royal Premiere of the film Ali in London on December 11, 2001. Smith starred as Muhammad Ali in the film. (Photo by Dave Hogan/Getty Images)

A little blue penguin which was found at Papamoa Beach, covered in oil after the Liberian cargo ship, Rena, hit a reef, on October 7, 2011, in Tauranga, New Zealand. Reports of an oil sheen have been spotted on the surface of the water surrounding the ship and two penguins have been found covered in oil. (Photo by SUNLIVE New Zealand/Getty Images)

A general view of atmosphere during 2016 New York Comic Con – Day 1 on October 6, 2016 in New York City. The annual event offers pop culture fans exhibitors and displays of popular video games, movies and comic books and many people attending dress as their favorite character. (Photo by Daniel Zuchnik/Getty Images)

Performers eat their lunch before the start of the New Year's Day Parade in London, January 1, 2016. (Photo by Kevin Coombs/Reuters)

Girls suffering from dwarfism take part in the disability pride parade in New York, July 12, 2015. The parade grand marshal was former U.S. Sen. Tom Harkin, the Iowa Democrat who 25 years ago sponsored the Americans With Disabilities Act. (Photo by Eduardo Munoz/Reuters)

Sheep walk as they are herded to summer pastures in Serra da Estrela, near Seia, Portugal June 27, 2015. In late June, shepherds young and old in the Seia region of central Portugal start guiding sheep, goats and cattle to the Serra da Estrela, the country’s highest mountains, in search of better pastures. There they stay until the end of September. Modern-day shepherds may have mobile phones to keep in touch with family and friends, but their lifestyle has changed little for centuries. The sound of cowbells and the bark of longhaired mastiffs starts early in the morning as the animals – often decorated with traditional woollen balls on their horns – are herded up steep, narrow paths. (Photo by Rafael Marchante/Reuters)

People cheer as the ball drops at midnight in Times Square on January 1, 2015 in New York City. An estimated one million people from around the world are expected to pack Times Square to ring in 2015. (Photo by Andrew Theodorakis/Getty Images)