A polar bear plays with a pylon during celebrations marking its first birthday in an enclosure at Tierpark Hellabrunn zoo in Munich December 9, 2014. (Photo by Michaela Rehle/Reuters)

In this Wednesday, August 20, 2014 photo released by Red Bull, Maikel Melero of Spain warms up prior to the fifth stage of the Red Bull X-Fighters World Tour in the South African savanna of Pretoria, South Africa. (Photo by Joerg Mitter/AP Photo/Red Bull)

Juan Carlos Vilchez, 18-months-old, dressed to represent horror movie icon Chucky, looks into a storefront mall window, in Managua, Nicaragua, Friday, October 31, 2014. Juan Carlos is wearing a first place winner that he won earlier, for best Halloween costume in his age group. (Photo by Esteban Felix/AP Photo)

Golden gate Bridge Fog Thick early morning fog engulfed a huge world famous bridge so that only the very tip of it is visible above the clouds. Photographer Ali Erturk, 33, hiked to the spot at 4am to capture the stunning sight of the Golden Gates bridge immersed in the dense swirls of fog. (Photo by Solent News and Photo Agency)

“Falling Back To Earth” promises to be both spectacular and meditative, and presents a beautiful, thought-provoking vision of our relationship with the earth and with each other. (Photo by Dave Hunt/EPA)

A hot air balloon floats past an almost full rising moon on a warm fall evening near Encinitas, California October 5, 2014. (Photo by Mike Blake/Reuters)

A single object, a single shape, a single colour,' is how Anish Kapoor summed up Leviathan, his response to the Monumenta challenge this year. Radically departing from Christian Boltanski’s busy collage-like approach in Personnes for Monumenta 2010, Kapoor has filled the 13,500 square metre space with a single cavernous entity which surges through the Grand Palais roof.

Yaroslav Segeda at the top of a high rise building in Kudrinskaya Square, Moscow, Russia. (Photo by Yaroslav Segeda/Caters News)