High-rise buildings are partly covered by heavy fog at Hong Kong's Victoria Harbour Monday, March 20, 2017. Fog blanketing Hong Kong is common in springtime and may greatly affect shipping and aviation. (Photo by Vincent Yu/AP Photo)

Thai officials arrive for morning alms as part of celebrations for the 68th birthday of Thai King Maha Vajiralongkorn Bodindrade​bayavarangkun, at Sanam Luang in Bangkok, Thailand, 28 July 2020. (Photo by Diego Azubel/EPA/EFE)

A vendor (C) serves customers at a vegetable market as a commuter train passes in Jakarta October 2, 2015. Indonesia's high annual inflation rate cooled in September and should drop more by year-end, but it likely will be 2016 before the central bank can cut interest rates to help an economy growing at its slowest pace in six years. (Photo by Reuters/Beawiharta)

People wearing face masks to help curb the spread of the coronavirus wait to walk across a traffic intersection in Osaka, western Japan, Thursday, November 26, 2020. (Photo by Hiro Komae/AP Photo)

In a photo taken on November 27, 2016 a female traffic police officer directs traffic on a road in Pyongyang. Believed to be hand-picked for their looks, Pyongyang's female traffic police are a familiar sight at intersections around the capital, where traffic volumes have noticeably increased in recent years. (Photo by Ed Jones/AFP Photo)

Visitors hold mobile devicecs in front of the golden burial mask of King Tutankhamun during the first day for visitors after the official opening of the Grand Egyptian Museum in Giza, Egypt, Tuesday, November 4, 2025. (Photo by Amr Nabil/AP Photo)

Children play on top of a cargo ship that was swept during the onslaught of Typhoon Haiyan in Tacloban city in central Philippines November 2, 2015, ahead of the second anniversary of a devastating typhoon that killed more than 6,000 people in central Philippines. The front part of the ship was retained in the area and made into a memorial and will be inaugurated on November 8 to commemorate the second anniversary of Typhoon Haiyan. (Photo by Erik De Castro/Reuters)

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.