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.

Circus artists perform at the International Circus Show started in Avenue Habib Bourguiba in Tunis, Tunisia on June 23, 2022. (Photo by Yassine Gaidi/Anadolu Agency via Getty Images)

A pro-democracy demonstrator fights with a Soviet soldier on top of a tank parked in front of the Russian Federation building on August 19, 1991, after a coup toppled Soviet President Mikhail Gorbachev. The same day, thousands in Moscow, Leningrad, and other cities answered Russian Republic President Boris Yeltsin's call to raise barricades against tanks and troops. (Dima Tanin/AFP/Getty Images)

A runner takes part in the International World's coldest marathon at minus 53 degrees (–63.4 Fahrenheit) near Oymyakon, the republic of Sakha, also known as Yakutia, Russian Far East, Saturday, January 22, 2022. Sixty five runners, including athletes from the United Arab Emirates, United States and Belarus, started the run at extremely low temperature in Oymyakon, Yakutia's Pole of Cold. The international team of men and women ran full distance and half-marathon. (Photo by Ivan Nikiforov/AP Photo)

Female Kurdish Peshmerga fighters affiliated with Iran's separatist Kurdistan Freedom Party (PAK), are pictured at a base in an undisclosed location in the Arbil province, the capital of the autonomous Kurdish region of northern Iraq, on December 1, 2022. Iranian-Kurdish rebel groups have for decades sought refuge in northern Iraq's autonomous Kurdistan region, but they have recently come under fresh fire amid weeks of protests in the neighbouring Islamic republic. (Photo by Safin Hamed/AFP Photo)

People take part in the 2022 National Carnival Parade, on the Malecon of Santo Domingo, Dominican Republic, 06 March 2022. The first post-pandemic national parade of the Dominican carnival had to appeal this Sunday to its color, enthusiasm and creativity to overcome the inclement rains that delayed and hindered the most popular and unbridled cultural display in the country. (Photo by Orlando Barria/EPA/EFE)

Visitors enjoy a walk accross a suspension bridge for the pedestrians that is the longest such construction in the world shortly after its official opening at a mountain resort in Dolni Morava, Czech Republic, Friday, May 13, 2022. The 721-meter (2,365 feet) long bridge is built at the altitude of more than 1,100 meters above the sea level. It connects two ridges of the mountains up to 95 meters above a valley between them. (Photo by David W. Cerny/Reuters)

Migrants climb through the windows of a train bound for Serbia at the train station in Gevgelija, The Former Yugoslav Republic of Macedonia, 19 July 2015. Thousands of migrants who crossed Greece are on their way through Macedonia towards Serbia in order to access other European countries. Hungary in mid-July started to put up a fence on its border with Serbia, which makes the situation with the migrants in the transit countries even more complicated. The European countries on 20 July will discuss the quota of how many migrants each country should accept. (Photo by Georgi Licovski/EPA)