A gallery assistant holds a rare 14th century time-telling device device in Bonhams auction house on December 9, 2011 in London, England. The instrument, which dates from 1396 and was discovered in a shed in Queensland, Australia, is due to be auctioned on December 13, 2011 and is expected to fetch 200,000 GBP. (Photo by Oli Scarff/Getty Images)

Afghan police officers secure a transportation headquarters that was besieged for two days last weekend, on May 14, 2011 in Kandahar, Afghanistan. Taliban gunmen and suicide bombers unleashed a major assault May 7, 2011 on locations in Kandahar that included the governor's compound, the mayor's office, police stations, and an intelligence agency headquarters. (Photo by Majid Saeedi/Getty Images)

Apple CEO Steve Jobs delivers the keynote address at the 2011 Apple World Wide Developers Conference at the Moscone Center on June 6, 2011 in San Francisco, California. Apple CEO Steve Jobs returned from sick leave to introduce Apple's new iCloud storage system and the next versions of Apple's iOS and Mac OSX. (Photo by Justin Sullivan/Getty Images)

Two rare ceramic heads from a series by Japanese ceramicist Takahiro Kondo are displayed at the “Masterpiece London” Auction on June 29, 2011 in London, England. The second “Masterpieces London” sale is currently underway at The Royal Hospital Chelsea, showcasing fine and decorative arts, jewellery, classic cars, fine wines and sculpture from over 30 dealers. The event takes place from June 30 – July 5, 2011. (Photo by Dan Kitwood/Getty Images)

Legend by Damien Hirst in the gardens of Chatsworth House on September 9, 2011 in Chatsworth, England. The never before seen work by Hirst is part of the Beyond Limits exhibition of modern and contemporary sculpture displayed in the gardens of Chatsworth by Sotherby's between 9th September to 30th October 2011. (Photo by Christopher Furlong/Getty Images)

Death Muammar Muhammad Abu Minyar al-Gaddafi (7 June 1942 – 20 October 2011) in Misrata on October 20, 2011. The veteran strongman was killed on as new regime forces crushed the last pocket of resistance in his hometown Sirte, the National Transitional Council said. (Photo credit should read MAHMUD TURKIA)

A Royal Air Force search and rescue helicopter prepares to leaves RAF Valley as the search continues for the crew of cargo vessel The Swanland which sank off north Wales on November 27, 2011 in Anglesey, Wales. (Photo by Christopher Furlong/Getty Images)

“Rivers Forgotten” is a journey through the passages and portals of the underground waterways that lie unseen below cities. Self-taught photographer Jeremy Kai brings these forgotten landscapes to light. Photo: Beneath the Toronto area, 2011. (Photo by Jeremy Kai)