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.

Hungarian Puli sheep dog, Fee, jumps over a hurdle during a preview for a pedigree dog show in Dortmund on Thursday April 24, 2008. (Photo by Frank Augstein/AP Photo)

Unforgiving temperatures of up to 60℃ (140℉) beat down on these saltminers on a daily basis. The mines, situated in the Afar Triangle in Ethiopia, stretch across 38,000 sq miles and at their lowest point are more than 300ft below sea level. Joel Santos travelled to capture the area’s dry, brutal beauty. Here: Dromedaries and donkeys are used to transport the salt. (Photo by Joel Santos/Barcroft Images)

Folk artists perform at an local opera ahead of Lantern Festival to celebrate Lunar New Year, in Tianshui, Gansu province, China, February 10, 2017. (Photo by Reuters/Stringer)

38 year old Prabhat Sinha, from Assam, carries a load of coal weighing 60kg's, supported by a head-strap, as he ascends the staircase of a coal mine on April 16, 2011 near the village of Khliehriat, in the district of Jaintia Hills, India. (Photo by Daniel Berehulak/Getty Images)

Mount Sinabung looks calm as seen from Karo, North Sumatra at dawn on August 8, 2021. (Photo by Tibta Nangin/AFP Photo)

A shorn alpaca walks in a grass field at Alpaca-Land farm in Unken in the Austrian province of Salzburg, Sunday July, 6, 2014. The annual shearing makes the animals more comfortable for the summer months. (Photo by Kerstin Joensson/AP Photo)

In this Friday, January 7, 2011 photo, people carry baskets of coal scavenged illegally at an open-cast mine in the village of Bokapahari in the eastern Indian state of Jharkhand where a community of coal scavengers live and work. The world's biggest coal users – China, the United States and India – have boosted coal mining in 2017, in an abrupt departure from last year's record global decline for the heavily polluting fuel and a setback to efforts to rein in climate change emissions. (Photo by Kevin Frayer/AP Photo)