Pedestrians and traffic cross Tower Bridge as viewed through a glass viewing platform on the high-level Walkways during a preview to launch the new viewing experience at the Tower Bridge Exhibition centre in London on November 10, 2014. The new glass flooring at the Tower Bridge Exhibition 42 metres above the river Thames will allow visitors to gaze down on the bridge and river and allow them to experience the bridge opening from above. (Photo by Andrew Cowie/AFP Photo)

A woman reacts as she joins around a thousand New Year swimmers, many in costume, braved freezing conditions in the River Forth in front of the Forth Rail Bridge during the annual Loony Dook Swim on January 1, 2013 in South Queensferry, Scotland. Thousands of people gathered last night to see in the New Year at Hogmanay celebrations in towns and cities across Scotland. (Photo by Jeff J. Mitchell)

This handout picture taken by Pleiades satellite and released on September 27, 2013 shows a small island of mud and rock created by the huge earthquake that hit southwest Pakistan has fascinated locals but experts – who found methane gas rising from it – say it is unlikely to last long. The 7.7-magnitude quake struck on September 25 in Baluchistan's remote Awaran district, killing at least 271 people and affecting hundreds of thousands. The island is about 60 to 70 feet (18 to 21 metres) high, up to 300 feet wide and up to 120 feet long and sits about 650 feet from the coast. (Photo by AFP Photo/CNES/Distribution Astrium Services)

Model Irina Shayk and Arthur Sales present the new collection “Xti 2011-12” on March 14, 2011 in Madrid, Spain. (Photo by Carlos Alvarez/Getty Images)

A gallery assistant at the Saatchi Gallery admires a sculpture by artist Dirk Skreber entitled “Untitled (Crash 1)” on May 26, 2011 in London, England. The sculpture features in the Saatchi Gallery's exhibition, “The Shape of Things to Come: New Sculpture” which showcases work from 20 international artists. (Photo by Oli Scarff/Getty Images)

Fireworks light up the London skyline and Big Ben just after midnight on January 1, 2012 in London, England. Thousands of people lined the banks of the River Thames in central London to see in the New Year with a spectacular fireworks display. (Photo by Peter Macdiarmid/Getty Images)

Whitney Houston's body arrives at Whigham Funeral Home on February 13, 2012 in Newark, New Jersey. (Photo by Dave Kotinsky/Getty Images)

In this Saturday, March 21, 2015 photo, a porter rests carrying supplies for the upcoming climbing season, near the Everest Base camp, Nepal. Nepal has cleared more than 300 mountaineers to climb Mount Everest after they had to abandon last year's efforts when an ice avalanche killed 16 guides in the mountain's deadliest disaster, an official said on March 20. The three-month climbing season for Everest, the world's tallest mountain, begins in March. (Photo by Tashi Sherpa/AP Photo)