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.

A young girl gives a banana to a tamed baboon on the outskirts of Beira, Mozambique, Sunday, March, 31, 2019. Cholera cases among cyclone survivors in Mozambique have jumped to 271, authorities said. So far no cholera deaths have been confirmed. (Photo by Tsvangirayi Mukwazhi/AP Photo)

An Elvis impersonator is reflected in the window of the Elvis Express at Central Station in Sydney, Australia, on Thursday, January 5, 2023. Hundreds of Parkes Elvis Festival attendees will board the Elvis Express train from Sydney's Central Station on Thursday for a windy 450-kilometre journey to the central west. (Photo by Steven Saphore/Anadolu Agency via Getty Images)

It's taken roughly five months, but a massive iceberg has separated from Antarctica's Pine Island Glacier. According to NASA's Earth Observatory, the estimated size of this iceberg, named B-31, is around 660 square kilometres (33 km long by 20 km wide) – a city-sized block of ice that has slowly migrated away from the continent, and is now floating out to sea. Take a look at some massive icebergs afloat in the oceans. Photo: File photo of an iceberg floating near a harbour in the town of Kulusuk, east Greenland August 1, 2009. (Photo by Bob Strong/Reuters)

Gold medalist Mujinga Kambundji, of Switzerland, left, and silver medalist Ewa Swoboda, of Poland, celebrate after finishing the Women 60 meters final at the European Athletics Indoor Championships at Atakoy Arena in Istanbul, Turkey, Friday, March 3, 2023. (Photo by AP Photo/Stringer)

South African surfer Andy Marr rides a wave at Dungeons offshore reef in the Atlantic Ocean outside Cape Town, South Africa, 01 September 2016. The big wave surfing season is at its peak with winter swells driven by storms in the South Atlantic breaking on the Cape's outer reefs providing good conditions. Big wave surfers are competing in the 2016 Striped Horse Challenge and Rebel Sessions big wave competitons symultaneously throughout the season. (Photo by Nic Bothma/EPA)

Archie, a Chinese Crested dog, sits with his tongue out before the start of the 20th Annual Ugliest Dog Competition at the Sonoma-Marin Fair June 20, 2008 in Petaluma, California. Owners of ugly dogs travel to Petaluma from all over the country to participate in the annual contest. (Photo by Justin Sullivan/Getty Images)