Drummers perform during rehearsals at the Bird's Nest National Stadium ahead of the IAAF Athletics World Championships in Beijing on August 20, 2015. The Athletics World Championships will be held at the stadium from August 22 to 30. (Photo by Greg Baker/AFP Photo)

A Rajasthani folk dance artist performs while standing on two glasses during the “Dhora Ri Mahak” festival in Bhopal, India, 07 January 2015. The event is being organised by the “Indira Gandhi Rashtriya Manav Sangrahalaya” anthropology museum. (Photo by Sanjeev Gupta/EPA)

David Bowie, 1974. David Bowie's quirky character and style was perfectly encapsulated in this shot by Terry O'Neill, which shows the music legend posing next to a barking dog on the artwork for his 1974 album “Diamond Dogs” in London. (Photo by Terry O'Neill)

Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

These stunning photographs show the changing face of a majestic centuries old Kazakh pastime tradition that still lives in the lands of mongolia – eagle hunters. Photo: 13 year old Irka Bolen with his eagle. Tradition wise, when a boy turns 13, then are strong enough to hold the weight of a fully grown eagle. (Photo by Asher Svidensky/Caters News)

These heart-warming photograph show an incredible bond between a wild lioness and the men fighting to save her species. The picture show Sirga – a 110lb lioness – and her adopted pride Valentin Gruener (not pictured) and Mikkel Legarth. Incredibly she treats the two men just like she would other lions and with their help she can now hunt for prey on her own. As a cub she was driven out from a pride and rescued by German and Danish duo Valentin and Mikkel who could not stand by and watch her die. She is now a beacon for hoped success of the Modisa Wildlife Project, founded in Botswana, Africa, by Valentin and Mikkel with the hope of saving the lion population. (Photo by Caters News)

These are the stomach-churning pictures of the swing at the end of the world – a rickety wooden swing hanging over a precipice 2,660 metres above sea level – and not a seatbelt in sight. (Photo by Caters News)

Racegoers make their way home after Ladies Day on the second day of the Grand National meeting at Aintree Racecourse on April 9, 2010 in Aintree, England. Friday is traditionally Ladies day at the three-day meeting of the world famous Grand National, where fashion is as important as the racing. (Photo by Christopher Furlong/Getty Images)