Riot police face off with demonstrators at the “Occupy Denver” camp on October 29, 2011 in Denver, Colorado. Following a march by protesters, police moved in on their encampment to tear down recently erected tents. They arrested numerous protesters, pepper-sprayed others and others reportedly fired rubber bullets at the crowd during the confrontation. (Photo by John Moore/Getty Images)

Protestors affiliated with the Occupy Wall Street movement block the entrance to the Iowa Democratic Party headquarters during a protest on December 29, 2011 in Des Moines, Iowa. Thirteen people were arrested during the protest. (Photo by Andrew Burton/Getty Images)

An animal rights protester demonstrates for the abolition of bull runs and bullfights, three days before the start of the famous running of the bulls San Fermin festival in Pamplona, northern Spain, July 4, 2015. (Photo by Eloy Alonso/Reuters)

A policewoman tries to stop an anti-Occupy protester from breaking a police cordon to charge at pro-democracy protesters during a confrontation in Hong Kong October 13, 2014. Hundreds of unidentified people, some wearing masks, tried to break down protest barriers in the heart of Hong Kong's business district on Monday, scuffling with protesters who have occupied the streets for the past two weeks. (Photo by Bobby Yip/Reuters)

(2nd from R) Miss Georgia Betty Cantrell reacts to advancing, en route to victory, at the Miss America Pageant at Boardwalk Hall, in Atlantic City, New Jersey, September 13, 2015. (Photo by Mark Makela/Reuters)

The Peugeot vehicle of driver Carlos Sainz of Spain is seen at the technical verification area ahead of the Dakar Rally 2016 in Buenos Aires, Argentina, January 1, 2016. (Photo by Marcos Brindicci/Reuters)

A tank crew competes in an individual race at a regional stage of the 2016 Tank Biathlon Competition at the Anastasyevsky training ground, March 1, 2016, Khabarovsk Territory, Russia. (Photo by Yuri Smityuk/TASS/Newscom)

The Proton rocket, that will launch the ExoMars 2016 spacecraft to Mars, is transfered to the launchpad at the Baikonur cosmodrome, Kazakhstan, in this handout photo released by European Space Agency (ESA) on March 11, 2016. (Photo by Stephane Corvaja/Reuters/ESA)