Amundsen-Scott South Pole Station experiences months of darkness. The sun dips below the horizon on March 21, after which follows several weeks of twilight before complete darkness results. Photo taken on June 25, 2009. (National Science Foundation/Jeremy Johnson)

Lake Baikal is the world's oldest lake, at 25 million years (possibly older), and deepest, averaging 744.4 metres (2,442 ft).

Located in the south of the Russian region of Siberia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, it is the most voluminous freshwater lake in the world, containing roughly 20% of the world's unfrozen surface fresh water.

Meenakshi Amman Temple and Meenakshi Amman Kovil is a historic Hindu temple located on the southern bank of the Vaigai River in the temple city of Madurai, Tamil Nadu, India. It is dedicated to Parvati, known as Meenakshi, and her consort, Shiva, here named Sundareswarar.

People dance in a park on a foggy day in Huai'an, Jiangsu province, China October 10, 2017. (Photo by Reuters/China Stringer Network)

Spacewalker Mark Vande Hei took his own photograph during the first spacewalk of 2018, on January 23, 2018. These sky-high pictures are better known as “space-selfies”. (Photo by Mark Vande Hei/NASA)

The homemade Airbus A320 jet plane made by Chinese farmer Zhu Yue is being built at an open space in Kaiyuan city, northeast China's Liaoning province on February 4, 2018. (Photo by Imaginechina/Rex Features/Shutterstock)

Katie Loynes of the Blues attempts to mark the ball during the AFLW Preliminary Final match between the Carlton Blues and the Fremantle Dockers at Ikon Park on March 23, 2019 in Melbourne, Australia. (Photo by Mike Owen/Getty Images)