A Sydney Aquarium diver uses a vacuum to clean the gravel in the Great Barrier Reef tank as a Ray Shark swims by September 26, 2006 in Sydney, Australia. The Aquarium is undergoing its annual spring clean to prepare for the school holidays using vacuums, along with sea creatures like Sea Cucumbers, Sea Urchins, Cleaner Wrasse Fish and Sea Stars to help complete the job. (Photo by Ian Waldie/Getty Images)

Students from John Moores' University celebrate and pose for family photographs as they take part in their degree congregations at Liverpool's Anglican Cathedral on July 13, 2011 in Liverpool, England. Thousands of students are taking part in graduations across Britain and will begin looking for employment. According to recent surveys there are currently 83 graduates chasing every job vacancy. (Photo by Christopher Furlong/Getty Images)

Route engineer Richard Winter stands in front of a pile of road salt at the Birchanger Depot on November 8, 2011 near Bishop's Stortford, England. (Photo by Peter Macdiarmid/Getty Images)

Members of the public continue to pay their respects at the scene of a hit and run following civil disturbances in the Winson Green area on August 12, 2011 in Birmingham, England. Police are continuing investigations after three people – reportedly trying to protect shops from rioting and looting in Dudley Road – were struck by a car and killed during rioting. Police have so far arrested over 1,000 people following rioting which erupted over a four-day period across the UK. (Photo by Jeff J Mitchell/Getty Images)

In this Monday, March 10, 2014 photo, a 9,000 year-old mask is on display at the Israel Museum in Jerusalem. The exhibition called “Face To Face” shows eleven stone masks, said to have been discovered in the Judean desert and hills near Jerusalem, which date back 9,000 years and offer a rare glimpse at some of civilization's first communal rituals. (Photo by Tsafrir Abayov/AP Photo)

A three wheeled “cabin” scooter manufactured by German aircraft engineers Messerschmitt & Co at factories in Regensburg. (Photo by Hans Enzwieser/BIPs/Getty Images). 1955

This series of pictures shot by satellite, show the man-made world as astronauts see it. Artist Benjamin Grant uses Google Earth to find the most compelling satellite images of human civilization. The stunning pictures of sprawling metropolises and vast reservoirs are sometimes unidentifiable until zoomed in. In order to find an extraordinary picture in the practically endless supply of satellite data, Benjamin focuses on the themes of current events or environmental issues. Here: Industrial Sector, Tokai, Japan. (Photo by Benjamin Grant/Digital Globe/Caters News)