General view of Chilean Calbuco volcano from Puerto Montt, located at 1000 km southern Santiago de Chile, Chile, 22 April 2015. Due to the eruption of the volcano with a smoke column 20 km high, authorities declared a red alert and ordered the evacuation of around 1500 inhabitants of Ensenada, Alerce, Colonia Río Sur and Correntoso towns. (Photo by Alex Vidal Brecas/EPA)

Students receive a group punishment during a military-style close-order drill class at the Qide Education Center in Beijing February 19, 2014. The Qide Education Center is a military-style boot camp which offers treatment for internet addiction. As growing numbers of young people in China immerse themselves in the cyber world, spending hours playing games online, worried parents are increasingly turning to boot camps to crush addiction. Military-style boot camps, designed to wean young people off their addiction to the internet, number as many as 250 in China alone. (Photo by Kim Kyung-Hoon/Reuters)

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)

The Potala Palace in Lhasa, Tibet Autonomous Region, China, was the chief residence of the Dalai Lama until the 14th Dalai Lama fled to India during the 1959 Tibetan uprising. It is now a museum and UNESCO World Heritage Site.

Artist Ted Harrison makes final adjustments to his artwork created with poppies on the floor of St. Paul's Cathedral on November 10, 2011 in London, England. Mr. Harrison created the work on a 30 foot disc under the main dome of the cathedral with the intention of drawing attention to the 250,000 children worldwide currently under military orders. (Photo by Peter Macdiarmid/Getty Images)

The Stone Forest or Shilin is a notable set of limestone formations located in Shilin Yi Autonomous County, Yunnan Province, People's Republic of China, near Shilin approximately 120 km (75 mi) from the provincial capital Kunming. The tall rocks seem to emanate from the ground in the manner of stalagmites, with many looking like petrified trees thereby creating the illusion of a forest made of stone. Since 2007, two parts of the site, the Naigu Stone Forest (乃古石林) and Suogeyi Village (所各邑村), have been UNESCO World Heritage Sites as part of the South China Karst.

Boys play football in a shantytown of Olinda, about 18 km from Recife in northeastern Brazil, on June 18, 2013 as the FIFA Confederations Cup Brazil 2013 football tournament is being held in the country. The historic centre of Olinda is listed as an UNESCO World Heritage Site. (Photo by Yasuyoshi Chiba/AFP Photo)