The adventurous explorers have snapped themselves in shark-infested waters, at the side of an active volcano, atop a Hong Kong skyscraper surrounded by toxic smog, and even perched on the top of iconic Rio statue of Christ the Redeemer. Here: Ervin Punkar using a selfie stick to take a photo from the very top of the 600ft TV tower in Tartu, Estonia. (Photo by Ervin Punkar/Caters News Agency)

In this Sunday, March 12, 2017, picture a Don Sphinx cat reaches for a judge while being evaluated, in Bucharest, Romania. More than 1,500 dogs and 150 cats from twelve countries were evaluated during a three day pet show and competition in the Romanian capital. (Photo by Vadim Ghirda/AP Photo)

Winner. “I took this picture of a woman in traditional clothing in Cartagena, Colombia”. PAUL GOLDSTEIN, JUDGE: “The blaze of colour from every angle, the boldness of the picture, taken from behind, which gives it so much more allure and frankly a superb get up. Did I mention the colours? Oh, and that looks suspiciously like a Nokia”. (Photo by Stanislav Shmelev/The Guardian)

The report, prepared by the Sustainable Development Solutions Network (SDSN) and the Earth Institute at Columbia University, showed Syria, Afghanistan and eight sub-Saharan countries as the 10 least happy places on earth to live. The top 10 this year were Denmark, Switzerland, Iceland, Norway, Finland, Canada, Netherlands, New Zealand, Australia, and Sweden. Denmark was in third place last year, behind Switzerland and Iceland. The bottom 10 were Madagascar, Tanzania, Liberia, Guinea, Rwanda, Benin, Afghanistan, Togo, Syria and Burundi. The United States came in at 13, the United Kingdom at 23, France at 32, and Italy at 50. Here: #8. NEW ZEALAND: A woman dives from a platform into a giant air bed at a park in Palmerston North September 29, 2011. (Photo by Marcos Brindicci/Reuters)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

Indian Christians take part in Christmas prayers at the Infant Jesus church in Bangalore, India, 25 December 2020. Most Christians celebrate Christmas on 25 December to commemorate the birth of Jesus, the central figure of Christianity. (Photo by Jagadeesh N.V./EPA/EFE)

Two men using an electric power saw to fell a tree circa 1940's. (Photo by Keystone View/FPG/Getty Images)