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.

This picture taken on July 15, 2014 shows a bridge submerged in floodwaters in the ancient town of Fenghuang, central China's Hunan province. Rainstorms lashed central China's Hunan Province and southwest China's Guizhou Province, affecting over 1 million people and flooding a historical town, state media reported. (Photo by AFP Photo)

A Hindu holy man, or sadhu, smokes marijuana on a chillum (pipe) at the premises of Pashupatinath Temple during the Shivaratri festival in Kathmandu February 27, 2014. Hindu holy men from Nepal and India come to this temple to take part in the Shivaratri festival. Celebrated by Hindu devotees all over the world, Shivaratri is dedicated to Lord Shiva, and holy men mark the occasion by praying, smoking marijuana or smearing their bodies with ashes. (Photo by Navesh Chitrakar/Reuters)

A dog runs as Palestinian boys ride donkeys carrying vegetable after working in their field in the West Bank village of Nassariya near Nablus November 30, 2016. (Photo by Abed Omar Qusini/Reuters)

A woman travels on a train stopping at a subway station visited by foreign reporters in central Pyongyang, North Korea on April 14, 2017. (Photo by Damir Sagolj/Reuters)

A Grevy’s zebra gets itself noticed at ZSL Whipsnade Zoo in Whipsnade, England on April 20, 2018. (Photo by Tony Margiocchi/Barcroft Media)

In this photograph taken on April 28, 2018, Afghan children work at a coal yard on the outskirts of Jalalabad, Afghanistan. (Photo by Noorullah Shirzada/AFP Photo)

People carry lychee for sale on a motorbike on a street in Luc Ngan, Bac Giang province, Vietnam, 22 June 2016. Lychee output in Bac Giang province is expected to reach 130,000 tonnes this year. China is still Vietnam's main lychee export market so far, buying around 60 percent of the annual crop, according to official reports. (Photo by Luong Thai Linh/EPA)