People with his face covered in oil and soot and carrying bull horns representing a devil join a carnival festival on February 14, 2015 in Luzon, Spain. (Photo by David Ramos/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)

“There Were Early Indications that Maxine was Not a Good Fit for the Surgical Team”. (Photo by Studio d'Xavier)

A wounded member of the Afghan police reaction force waits for treatment in Alingar, Laghman province, on April 30, 2012. A bomb exploded next to opium poppy fields during a poppy eradication campaign in, wounding two Afghan policemen, police officials said. (AP Photo/Rahmat Gul)

This artist's scoreboard displays a fictional game between Mars and Earth, with Mars in the lead. It refers to the success rate of sending missions to Mars, both as orbiters and landers. Of the previous 39 missions targeted for Mars from around the world, 15 have been successes and 24 failures. For baseball fans, that's a batting average of .385. The United States has had 13 successes out of 18 attempts, or a “batting average” of .722. NASA's Curiosity rover, set to land on the Red Planet the evening of Aug. 5, 2012 PDT (morning of Aug. 6 EDT), will mark the United States' 19th attempt to tackle the challenge of Mars, and the world's 40th attempt. (Image by NASA/JPL-Caltech)

“A small British company with a dream of building a re-usable space plane has won an important endorsement from the European Space Agency (ESA) after completing key tests on its novel engine technology. Reaction Engines Ltd believes its Sabre engine, which would operate like a jet engine in the atmosphere and a rocket in space, could displace rockets for space access and transform air travel by bringing any destination on Earth to no more than four hours away”. – Chris Wickham via Reuters. Photo: Artist's impression of Skylon. (Photo by Reaction Engines Ltd)

Margaret Morris dancers exercising on the sands at Saint-Idesbald. (Photo by Fox Photos/Getty Images). August 1929

A young boy adjusts his friend's Adolf Hitler mask during a game on a street in King's Cross, London. (Photo by William Vanderson/Getty Images). 1938