A military band prepares to play the national anthems before Cuban President Raul Castro welcomes U.S. President Barack Obama at the Palacio de la Revolucion in Havana March 21, 2016. Barack Obama on Sunday became the first US president in 88 years to visit Cuba, touching down in Havana for a landmark trip aimed at ending decades of Cold War animosity. (Photo by Jonathan Ernst/Reuters)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

A model presents a creation from the Tom Ford Spring/Summer 2015 collection during London Fashion Week September 15, 2014. (Photo by Suzanne Plunkett/Reuters)

Located in East Java, Indonesia, Kawah Ijen is a volcano is home to the largest acidic crater lake in the world. What turns the waters of the lake in the 1 km caldera its beautiful turquoise color are the highly sulfuric gases emitted from the volcano underneath.

Cowboys Wyatt Williams (R) and David Thompson work to restrain a calf in order to give it medicine near Ignacio, Colorado June 12, 2014. The land where the cattle graze is leased from the Forest Service by third-generation rancher Steve Pargin. Several times a year, he and a crew led by his head cowboy, David Thompson, spend a week or more herding cattle from mountain range to mountain range to prevent them from causing damage to fragile ecosystems by staying in a single area too long. (Photo by Lucas Jackson/Reuters)

A girl wearing a butterfly headband poses for a picture near damaged buildings in the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria January 19, 2017. (Photo by Bassam Khabieh/Reuters)

A “Federahannes”, a jester figure from Rottweil, participates in the “Narrensprung” (jester jump) parade in Rottweil, southern Germany, Monday, February 27, 2016. About 4000 jesters paraded through the city among thousands of spectators. The Rottweil Narrensprung is the highlight of the Swabian-Alemannic Fastnacht and one of the traditional pre-Lenten carnival parades in southwestern Germany. (Photo by Michael Probst/AP Photo)

Two men play golf with a tennis ball as a snowstorm sweeps through Times Square, Tuesday, March 14, 2017, in New York. (Photo by Mark Lennihan/AP Photo)