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)

Salt-resistant plants grow in sand made up of small fish bones on the shore of the Salton Sea before sunrise in an area where a controversial development would create a new town for nearly 40,000 people on the northwest shore of the biggest lake in California, the Salton Sea, on March 21, 2012 south of Mecca, California. (Photo by David McNew/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)

Two rescued pangolins sit in a basket during a news conference in Bangkok on June 7, 2012. Thai customs rescued 110 pangolins worth about $35,500 that they say were to be sold outside the country as exotic food. The animals, hidden in a pickup truck, were seized at a customs checkpoint in Prachuap Khiri Khan province, south of Bangkok. (Photo by Sakchai Lalit/Associated Press)

People protest for greater action against climate change during the People's Climate March on September 21, 2014 in New York City. The march, which calls for drastic political and economic changes to slow global warming, has been organized by a coalition of unions, activists, politicians and scientists. (Photo by Andrew Burton/Getty Images)

Actors dressed up as zombies walk around while posing for photos with passers-by in New York's Times Square on Friday, October 10, 2014 as a promotion for the season premiere of AMC's “The Walking Dead” this Sunday, October 12, 2014. (Photo by Gordon Donovan)

Virgin Galactic's new spaceship N202VG (bottom L) is seen behind the WhiteKnightTwo carrier aircraft mothership (front), which landed safely after splitting from SpaceShipTwo, in a hangar at Mojave Air and Space Port in Mojave, California, November 4, 2014. (Photo by Lucy Nicholson/Reuters)