A man takes a photo of a radio antenna that's part of the Atacama Large Milimeter Array Observatory on March 12, 2013 at Llano de Chajnantor, about 43 miles (70 kilometers) from San Pedro de Atacama, Chile. The $1.5 billion ALMA facility, which had its official inauguration on March 13, is considered the world's most expensive ground-based observatory. (Photo by Felipe Trueba/EPA)

Members of the 1st Tennessee wait to take part in in a demonstration of a battle during ongoing activities commemorating the 150th anniversary of the Battle of Gettysburg, Friday, June 28, 2013, at at Bushey Farm in Gettysburg, Pa. Union forces turned away a Confederate advance in the pivotal battle of the Civil War fought July 1-3, 1863, which was also the war's bloodiest conflict with more than 51,000 casualties. (Photo by Matt Rourke/AP Photo)

In this undated photo made available by journal Nature on January 15, 2014, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, January 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (Photo by Markus Unsöld/AP Photo)

Vancouver B.C. April 20, 2014 Big Day to celebrate as thousand gathered in front of Vancouver Art Gallery to take part in the 420 Marijuana smoke in here in Vancouver on April 20, 2014. Here lots of free “joints” ready for the big moment. (Photo by Mark van Manen/PNG Staff Photographer/Ian Austin Province News/Vancouver Sun News & Web stories)

A participant takes part in the Bristol Park and Slide project, an interactive temporary installation by artist Luke Jerram set up in Park Street in the centre of Bristol, southwest England on May 4, 2014. Over 95,000 people applied for just 360 tickets to slide on inflatable lilos down a lubricated water slide in a town centre street. (Photo by Leon Neal/AFP Photo)

Performers take part in a rain soaked Notting Hill Carnival on August 25th, 2014 in London, England. Despite the bad weather over 1 million visitors are expected to attend the two-day event which is the largest of its kind in Europe. The event has taken place on the West London streets every August Bank Holiday weekend since 1964. (Photo by Mary Turner/Getty Images)

Singer, songwriter, actress and philanthropist Miley Cyrus, L, takes a selfie while doing her signature tongue-out pose with GMU students Samaria Moss, 18, C, of Spottsylvania, VA, Jaide Tarwid, 18, from Wisconsin, and Zimuzo Okala, 19, of Chesapeake, VA, (blocked) as Cyrus makes a campaign visit for Hillary Clinton and Tim Kaine in Northern Virginia at George Mason University on Saturday, October 22, 2016 in Fairfax, VA. (Photo by Jahi Chikwendiu/The Washington Post)