A street artist dances tango in Buenos Aires, Argentina, Tuesday, January 20, 2015. Tango is a partner dance that originated in the 1890's along the Rio de la Plata, the border between Uruguay and Argentina. UNESCO approved in 2009, a joint proposal by the two nations to include the dance in its Intangible Cultural Heritage List. (Photo by Rodrigo Abd/AP Photo)

A eunuch dances during a rally to mark the congregation of thousands of eunuchs from different parts of India, in Jammu, India, Friday, March 13, 2015. The term eunuchs is used in India to describe transvestites, transsexuals and others who identify themselves as neither male nor female but as a member of a third gender. They traditionally survive by begging, dancing at weddings or blessing newborn babies and are frequently subjected to discrimination. (Photo by Channi Anand/AP Photo)

Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

A visitor stands in the exhibition “I Am A Drop In The Ocean” dedicated to the artistic and visual expressions of the protests that shook the Ukraine from November 2013 until February 2014 at the Kuenstlerhaus gallery in Vienna, Austria, Thursday, April 10, 2014. The exhibition opens its doors from April 11 until May 23, 2014. (Photo by Ronald Zak/AP Photo)

In this Friday, March 28, 2014 photo, singers of the Moranbong Band, Jong Su Hyang, foreground, and Pak Mi Kyong, left perform on their stage in Pyongyang, North Korea. Step aside, Sea of Blood Opera. North Korean leader Kim Jong Un's favorite guitar-slinging, miniskirt-sporting girl group, the Moranbong Band, is back. And these ladies know how to shimmy. (Photo by Jon Chol Jin/AP Photo)

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.

Russian Police academy female cadets march during a rehearsal for the Victory Day military parade at Dvortsovaya (Palace) Square in St Petersburg, Russia, Wednesday, May 7, 2014. Victory Day, marking the defeat of Nazi Germany, is Russia's most important secular holiday celebrated on May 9. (Photo by Dmitry Lovetsky/AP Photo)

An Armatix employee holds a “smart gun” by the company at the Armatix headquarters in Munich May 14, 2014. The gun is implanted with an electronic chip that allows it to be fired only if the shooter is wearing a watch that communicates with it through a radio signal. If the gun is moved more than 10 inches (25 cm) from the watch, it will not fire. A Maryland gun shop owner has dropped his plan to be the first in the United States to sell the so-called “smart gun” after a backlash that included death threats. (Photo by Michael Dalder/Reuters)