Participants gather in the Union Square subway station during the annual No Pants Subway Ride on January 8, 2012 in New York City. The annual event is staged by the group Improv Everywhere which encourages people in dozens of cities worldwide to discard their pants while riding the subway. (Photo by Mario Tama/Getty Images)

Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

A woman sits next to a Gollum figure on the “Middle-earth Shuttle” subway train November 18, 2003 in New York City. The train's cars were decorated with Middle-earth creatures, vines, moss and stones to celebrate the November 18 DVD and VHS release of the Special Extended Edition of The Lord of the Rings: The Two Towers. (Photo by Mario Tama/Getty Images)

People walk past a downed tree in Central Park on October 31, 2011 in New York City. Central Park may lose 1,000 trees following a freak October snowstorm while the park only lost 125 trees due to Hurricane Irene. (Photo by Mario Tama/Getty Images)

Visitors attend a press preview of the 2012 Whitney Biennial at the Whitney Museum of American Art on February 27, 2012 in New York City. The contemporary art exhibition includes sculpture, photography, painting, installations, dance, theater, film and music and runs from March 1 through May 27. (Photo by Mario Tama/Getty Images)

Fireworks explode above Singapore's financial skyline at dusk as part of celebrations for the nation's 50th year of independence, Sunday, August 9, 2015, in Singapore. Singapore declared independence on August 9, 1965. (Photo by Wong Maye-E/AP Photo)

Storm chaser Brad Mack from Buena Park California videotapes a rotating supercell storm west of Newcastle, Texas April 9, 2013. Many of the storms in Tornado Alley that were forecast to be severe this week were taken out by a cold front from Canada. Picture taken April 9, 2013. (Photo by Gene Blevins/Reuters)

A Shi'ite worshiper bleeds after cutting his scalp in a ritual display of mourning during an Ashura commemoration ceremony outside Kadhimiya shrine on December 6, 2011 in Baghdad, Iraq. Ashura marks the death of Prophet Muhammad's grandson the revered Imam Hussein in Karbala, Iraq in 680 AD. Shi'ite festivals were prohibited during the time of Sunni dictator Saddam Hussein's rule. (Photo by Mario Tama/Getty Images)