Balloons participate in the Balloon Spectacular during Canberra Festival on March 10, 2012 in Canberra, Australia. The annual balloon festival in Canberra is considered one of the best in the world, and is unique in allowing patrons to float above Parliament, embassies and other government buildings. Canberra is celebrating its 99th birthday in 2012, with over 50 events in the 17 day Canberra Festival. (Photo by Cameron Spencer/Getty Images)

Buildings are seen near the ocean as reports indicate that Miami-Dade County in the future could be one of the most susceptible places when it comes to rising water levels due to global warming on March 14, 2012 in North Miami, Florida. Some cities in the South Florida area are starting to plan for what may be a catastrophic event for the people living within the flooding area. (Photo by Joe Raedle/Getty Images)

David Rawcliffe, house and monument steward at the National Trust's Chedworth Roman Villa cleans a Roman mosiac in the new environmentally-controlled conservation shelter on March 19, 2012 near Cirencester, England. Opened this month, the multi-million pound building allows visitors to walk on suspended walkways just above the 1600-year-old Roman floors and to see recently excavated mosaics not seen for 150 years, with more to be uncovered over the coming year. (Photo by Matt Cardy/Getty Images)

Protester Lauren Digioia wears police tape during an Occupy Wall Street protest in Union Square on March 19, 2012 in New York City. Protesters affiliated with the movement are gathering in Union Square today following 73 arrests at a six-month anniversary rally at Zuccotti Park over the weekend. (Photo by Mario Tama/Getty Images)

Circus performer and trampolinist Max Calaf Seve performs at a preview for NoFit State Circus new summer show at the Eden Project on March 29, 2012 in St Austell, England. This will be the second time that the NoFit Circus has performed in the world famous biomes of the Eden Project. The production will start on July 28 and run until September 2 before leaving Cornwall for a global tour. (Photo by Matt Cardy/Getty Images)

Israeli mounted policemen move crowds of Palestinian protestors during a demonstration marking Land Day in the east of the city on March 30, 2012 outside the old city of Jerusalem, Israel. Land Day, which began in 1976, marks the day Israeli forces killed six Palestinians during a protest against Israeli occupation of what Palestinians consider to be their land. Palestinians around the world will commemorate Land Day with protests and demonstrations. (Photo by Lior MizrahiGetty Images)

Amundsen-Scott South Pole Station experiences months of darkness. The sun dips below the horizon on March 21, after which follows several weeks of twilight before complete darkness results. Photo taken on June 25, 2009. (National Science Foundation/Jeremy Johnson)

Culinary Specialist 2nd Class Jaqueline Rodriguez subdues a simulated suspect after being sprayed with oleoresin capsicum (OC) spray during security training aboard the amphibious dock landing ship USS Comstock (LSD 45). (U.S. Navy photo by Mass Communication Specialist 2nd Class Joseph M. Buliavac/Released). May 10, 2011