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.

Contestant of the Muslimah World 2013, Obabiyi Aishah Ajibola (C) of Nigeria, is reflected in a mirror checking her make-up while contestants wait for a grand final during the Muslimah World competition in Jakarta on September 18, 2013. (Photo by Adek Berry/AFP Photo)

Protesters shield themselves as police beat them with sticks during a violent demonstration near the India Gate against a gang rape and brutal beating of a 23-year-old student on a bus last week, in New Delhi, India, December 23, 2012. The attack last Sunday has sparked days of protests across the country. (Photo by Kevin Frayer/Associated Press)

In this Thursday, April 11, 2013 photo, an Afghan woman peers through the the eye slit of her burqa as she waits to try on a new burqa in shop in the old town of Kabul, Afghanistan. (Photo by Anja Niedringhaus/AP Photo)

Chefchaouen or Chaouen is a city in northwest Morocco. It is the chief town of the province of the same name, and is noted for its buildings in shades of blue.

Manson Gerasimov of Russia and Agustina Piaggio of Argentina, representing the city of Rio Grande, Argentina, perform during the Stage style final round at the Tango World Championship in Buenos Aires, Argentina on August 23, 2018. (Photo by Marcos Brindicci/Reuters)

Paramedics care for a woman who is ill after the Geelong Cup on Geelong Cup day at Geelong Racecourse in Melbourne, Australia, 19 October 2016. The Geelong Racing Club was founded in March 1865 at a public meeting at the British Hotel. The first Geelong Cup was held in 1872 over a distance of two miles. (Photo by Tracey Nearmy/EPA)