Demonstrators throw fire bombs to riot police during violent protests in central Athens February 12, 2012. (Photo by Milos Bicanski/Getty Images)

Sean Phillips flies through the air as he demonstrates the JetLev water propelled jet pack that is strapped to his back at the Yacht & Brokerage Show on February 17, 2012 in Miami Beach, Florida. (Photo by Joe Raedle/Getty Images)

Nicole Scherzinger attends The BRIT Awards 2012 at the O2 Arena on February 21, 2012 in London, England. (Photo by Gareth Cattermole/Getty Images)

“Not for the faint of heart”. Casa Milà, better known as La Pedrera, is a building designed by the Catalan architect Antoni Gaudí and built during the years 1905–1910, being considered officially completed in 1912. It is located at 92, Passeig de Gràcia in the Eixample district of Barcelona, Catalonia, Spain. (Photo by Stefano Scarselli)

Saudi youths demonstrate a stunt known as “sidewall skiing” (driving on two wheels) in the northern city of Hail, in Saudi Arabia March 30, 2013. Performing stunts such as sidewall skiing and drifts is a popular hobby amongst Saudi youths. (Photo by Mohamed Al Hwaity/Reuters)

A round circle of smoke coming from the mouth of the Etna volcano is seen in the sky during an eruption on the southern Italian island of Sicily April 11, 2013. Mount Etna is Europe's tallest and most active volcano. (Photo by Antonio Parrinello/Reuters)

A visitor looks at a sculpture entitled “Couple Under an Umbrella, 2013” by artist Ron Mueck during the press day for his exhibition at the Fondation Cartier pour l'art contemporain in Paris April 15, 2013. (Photo by Charles Platiau/Reuters)

Four-man bicycle is powered by five chains and has brakes on both its wheels, 1948. The bike was built by Art Rothschild (top position) who broke three ribs while learning how to ride it. (Photo by Wallace Kirkland/Time & Life Pictures)