Space shuttle Discovery sits atop NASA's 747 Shuttle Carrier Aircraft (SCA) ready to transport it from Kennedy Space Center to the Washington D.C., on April 17, 2012 in Cape Canaveral, Florida. Following the retirement of the shuttle fleet, Discovery will fly to Washington for display at the Smithsonian's National Air and Space Museum. (Photo by Lofty Ambitions)

A tourist poses for a picture with the Sphinx at the Pyramids of Giza in Cairo, Egypt, on October 19, 2011. (Reuters/Jamal Saidi)

Lindsay Heimbach goes airborne while sledding down a hill on Mt. Lemmon December 27, 2008. (Photo by James Gregg/Arizona Daily Star)

An orphaned rhesus monkey and white dove that seemed to have lost its mate forged a special bond at the Neilingding Island-Futian National Nature Reserve in China. The monkey was born on the island but had strayed from its mother. Luckily, it was taken in by work staff in the protection center and became friends with the pigeon that had lingered there after possibly losing its mate. (Photo by CNImaging/Photoshot)

The Last Bell (we mean the bell that informs the pupils about the beginning or the ending of the lessons) is the traditional feast of the Russian pupils who leave the school. The Last School Bell feast occurs in the end of May, when the school year has already finished, but the final examinations have not begun yet. Luhansk (also known as Lugansk – a city in southeastern Ukraine), 2010. (Photo by X-F@ctor's bloG)

Armed Karo herdsman just back from protecting their cattle herds come down to the river to wash decorative clay markings off their bodies at the end of the day in the Omo Valley, South West Ethiopia. Dus, Omo Valley, Ethiopia, January 2008. (Photo by Brent Stirton/Discovery Communications)

British actress and humanitarian Audrey Hepburn, 1955. Jumpology. (Photo by Philippe Halsman)

A Black and Tan Coonhound named Harbor has the longest ears of any living dog, with measurements of 12.25 (31,12 cm) inches for the left ear and 13.5 (34,29 cm) inches for the right. (Photo by Ryan Schude/Guinness World Records via AP)