Students participate in an earthquake drill in their school in Santiago, November 13, 2014. Around one million people, which included students, teachers and parents, took part on Thursday in a drill that simulated a fictitious earthquake of a magnitude of 8.8 on the Richter scale, according to organizers. (Photo by Ivan Alvarado/Reuters)

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.

A young Hindu priest crawls under a cow as part of worship rituals during Tihar festival in Kathmandu, Nepal, Sunday, October 30, 2016. Cows are considered sacred to Hindus and are worshipped during Tihar festival, one of the most important Hindu festivals dedicated to the Goddess of wealth Laxmi. (Photo by Niranjan Shrestha/AP Photo)

People take part in a Halloween street party at Lan Kwai Fong on October 31, 2016 in Hong Kong. Halloween, a contraction of All Hallows' Evening, falls on the day before All Saints' Day on November 1, a holiday when Christians remember their deceased loved ones. (Photo by Lam Yik Fei/Getty Images)

Members of the Oath Keepers and general public return fire during a simulated attack as they take part in a tactical training session in northern Idaho, U.S. October 1, 2016. In April 2015 Reuters photographer Jim Urquhart was assigned to cover the Oath Keepers during a tour of the Sugar Pine gold mine in Oregon after the group of former cops, military, firefighters and other first responders had risen to prominence during a standoff in Nevada over land rights. (Photo by Jim Urquhart/Reuters)

Russian marines attached to the anti- submarine ship Admiral Tributs show their skills during a demonstration at a park in Manila on January 5, 2017, as part of their five- day port- of- call activities in the country' s capital. (Photo by Ted Aljibe/AFP Photo)

A dressed up participant without trousers takes part in the 2017 No Pants Subway Ride in New York, the United States, on January 8, 2017. The event, which first took place in New York in 2002, has become a yearly event attended by people in more than 60 cities across the globe. (Photo by Zou Zheng/Xinhua/Sipa USA)

People in Kathmandu joke that the face mask has now become part of the national dress – an indispensable accessory in an effort to protect themselves from the dust. Nepal has the worst air quality in the world, according to the Environmental Performance Index. (Photo by Pete Pattisson/The Guardian)