A General Atomics MQ-9 Reaper stands on the runway during “Black Dart”, a live-fly, live fire demonstration of 55 unmanned aerial vehicles, or drones, at Naval Base Ventura County Sea Range, Point Mugu, near Oxnard, California July 31, 2015. (Photo by Patrick T. Fallon/Reuters)

Supporters of former Democratic presidential candidate Bernie Sanders hold up posters at a “Black Men For Bernie” rally to gain support for third party candidates and protest the DNC during the 2016 Democratic National Convention on July 27, 2016 in Philadelphia, Pennsylvania. (Photo by Patrick T. Fallon/AFP Photo)

Mutant vehicles on the Playa are seen as approximately 70,000 people from all over the world gather for the 30th annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. September 3, 2016. (Photo by Jim Urquhart/Reuters)

A tank rolls out from a ship on a landing operation during military drills at the Black Sea coast, Crimea, Friday, September 9, 2016. Russia has deployed cruise missiles, multiple rocket launchers, tanks and its latest anti-aircraft system at massive military drills in Crimea. The drills which began across southern Russia and Crimea earlier this week and involve over 120,000 troops are some of the largest exercises Russia has held for years. (Photo by Pavel Golovkin/AP Photo)

Workers attempt to bring a tranquillised black rhino to the ground before dehorning in an effort to deter the poaching of one of the world's endangered species, at a farm outside Klerksdorp, in the north west province, South Africa, February 24, 2016. (Photo by Siphiwe Sibeko/Reuters)

A dog relaxes in an oxygen capsule “DOGS O2” at the Ownd Cafe on September 13, 2007 in Tokyo, Japan. The capsules come in a variety of sizes available for both dogs and cats for relaxation purposes. (Photo by Koichi Kamoshida/Getty Images)

Revellers take part in the “Canto a la Tierra” parade on January 3, 2018, during the Carnival of Blacks and Whites in Pasto, Colombia, the largest festivity in the south- western region of the country. More than 10,000 people among artists, craftsmen and revellers take part in the Blacks and Whites Carnival, which has its origins in the mix of the multiple Andean, Amazonian and Pacific cultural expressions. It is celebrated every year from January 2 to 6 in the city of Pasto and is part of UNESCO's Intangible Cultural Heritage of Humanity since 2009. (Photo by Luis Robayo/AFP Photo)