A David Cameron look-alike poses with a polar bear model outside the Houses of Parliament as part of a Greenpeace protest on May 13, 2011 in London, England. The environmental charity Greenpeace arranged the protest to highlight the first anniversary of David Cameron’s speech when he pledged to make his new government the greenest ever. In April 2006 Mr Cameron traveled by huskie-drawn sledge when he visited the island of Svalbard in Norway to witness the effects of climate change. (Photo by Oli Scarff/Getty Images)

Israeli magician Hezi Dean stands atop of a tower where he intends to remain for 35 hours, at Rabin square on May 18, 2011 in Tel Aviv, Israel. Dean started his most recent stunt Wednesday in an attempt to break the record of American illusionist and endurance artist David Blaine. Dean was raised on the 27-meters high tower Wednesday morning and aims to remain there with no food until Thursday evening, for a total of 35-hours. (Photo by Uriel Sinai/Getty images)

A traveller washes his horse in the River Eden in preparation for selling at the Appleby Horse Fair on June 3, 2011 in Appleby, England. Appleby Horse Fair has existed under the protection of a charter granted by James II since 1685. It is one of the key gathering points for the Romany, gypsy and traveling community. Appleby Horse Fair is attended by about 5,000 travelers who come to buy and sell horses. The animals are washed and groomed before being ridden at high speed along the “mad mile” for the viewing of potential buyers. (Photo by Christopher Furlong/Getty Images)

An arial view of Top Pearsy's Maize Maze in the shape of Harry Potter, on July 11, 2011 in York, England. Farmer Tom Pearcy has cut two portraits of Harry Potter in his crop of maize plants. With some subtle differences the two images create the world's largest spot the difference competition. At over 50m in diameter, and cut out of over 1 million living maize plants, the York Maze is the largest “Maize Maze” in Europe and one of the largest in the world. (Photo by Bethany Clarke/Getty Images)

“Fly cap for a vine snake”. A fly lands on the head of a vine snake in the Choco of Colombia. (Photo and caption by Robin Moore/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

“Stacked Supercell with Lightning”. This huge mesocyclone supercell was near the Nebraska / Kansas border on the night of June 22nd, 2012. What a stunning structure! (Photo and caption by Jennifer Brindley/National Geographic Traveler Photo Contest)

ATTENTION! All pictures are presented in high resolution. To see Hi-Res images – just TWICE click on any picture. In other words, click small picture – opens the BIG picture. Click BIG picture – opens VERY BIG picture.

“In 1967, Zhang Yaxin was 34 and working as a photojournalist at China’s state-controlled Xinhua News Agency when he was assigned to a top-secret government project. He was to be the official photographer of a new arts program led by Chairman Mao and his wife – the Model Operas. Though he was not to know it then, Zhang would spend the next seven years documenting the evolution of one of the most dramatic and elaborate attempts to redefine artistic sensibilities in modern art history”. – Chengcheng Jiang via TIME. Photo: Raid on the White Tiger Regiment, 1971. (Photo by Zhang Yaxin/Courtesy See+ Gallery, Beijing)

A mushroom cloud dwarfs a row of skyscrapers in what looks like a devastating nuclear bomb detonation. But thankfully this is just a spectacular weather-front blasting in from the tempestuous Rocky Mountains near Denver, Colorado, USA. The unbelievable shot is just one of many of the city's skyline taken by photographer Greg Thow. The 49-year-old has also captured equally stunning shots of lightning blasts and arching rainbows – all from the comfort of his balcony. (Photo by Greg Thow/Barcroft Media)