Mahouts return home with their elephants carrying grass to feed them on the eve of the rhino census in Kaziranga National Park in Assam state, India, 24 March 2015. Kaziranga will be closed to visitors for the next two days for a census of the rhinos commencing 25 March, in a previous census in 2013 in the park the population of the Indian rhinos was 2329. (Photo by EPA/Stringer)

Scarlett points at the huge ice sculpture of a bear during a Photocall for Magical Ice Kingdom at Hyde Park Winter Wonderland at Hyde Park on November 17, 2016 in London, England. It is the event's 10th anniversary this year. (Photo by Ben Perry/Getty Images)

A child plays the ice slide at the Ice-Snow World park in Harbin, capital of northeast China's Heilongjiang Province, January 5, 2017. The theme park which used about 330,000 cubic meters of ice and snow for construction opened on Thursday. (Photo by Xinhua/Barcroft Images)

Military helicopters fly in formation above a billboard with a picture of China's late Chairman Mao Zedong during a training session for the upcoming parade marking the 70th anniversary of the end of World War Two, on the outskirts of Beijing, July 2, 2015. Troops from Russia and Mongolia will march together with Chinese forces in a parade in Beijing in September to commemorate the end of World War Two, the government and state media said on Thursday, confirming the first two foreign participants. (Photo by Jason Lee/Reuters)

Kelimutu is a volcano, close to the small town of Moni about 50 km to the east of Ende, Indonesia in central Flores Island of Indonesia.

Angela Griffin attends the UK premiere of Hop held at The Vue west end on March 20, 2011 in London, England.

Three one-month-old lioness cubs are held by a keeper as they take their first outing on February 21, 2010 at the Ramat Gan Safari Park near Tel Aviv, Israel. The still unnamed cubs are the first triplet females to be born at the safari park and officials say their birth will ensure the continuity of the park's pride of lions. (Photo by David Silverman/Getty Images)

Hundreds of green bicycles are prepared as 960 of them await riders for the new year gala at the Temple of Heaven Park on December 29, 2011 in Beijing, China. Annual New Year countdown ceremony will be held at the park on December 31. (Photo by ChinaFotoPress/ChinaFotoPress via Getty Images)