Respect, Kronotsky nature reserve, Russia. The photographer’s cat, Ryska – her name means little lynx in Russian – stands outside their cabin and with aggressive posturing warns off a fox. In winter, foxes would regularly visit the cabin searching for food. If one peered in at the window, possible when the snow was deep, Ryska would sit on the other side, fur raised, and growl. When outside, she would hold her ground. The foxes were not always frightened and so encounters could be a sort of dance. (Photo by Igor Shpilenok/Unforgettable Behaviour/NHM)

A Russian police officer detains a teenager during rally protesting retirement age hikes in St. Petersburg, Russia, Sunday, September 9, 2018. A government plan to increase the age for collecting state pensions brought protests across Russia's 11 time zones on Sunday even though the opposition leader who called them was in jail. Nearly 300 people were reported arrested. (Photo by Roman Pimenov/Interpress photo via AP Photo)

Russian Emergency Situations employees help a girl to bath in the icy water on Epiphany at the Church of the Holy Trinity in Ostankino near TV Tower in Moscow, Russia, Friday, January 18, 2019. Across Russia, the devout and the daring are observing the Orthodox Christian feast day of Epiphany by immersing themselves in frigid water through holes cut through the ice of lakes and rivers. Epiphany celebrates the revelation of Jesus Christ as the incarnation of God through his baptism in the River Jordan. (Photo by Alexander Zemlianichenko/AP Photo)

Medical staff in Belgrade, Serbia on February 5, 2021. Vaccination of employees in the city's social protection institutions has begun at the Belgrade Fair, who have expressed interest in receiving the Russian Sputnik V vaccine, and according to the city secretary for social protection Natasa Stanisavljevic, about 150 employees in those institutions will receive the vaccine today and tomorrow. (Photo by Zoran Zestic/Tanjug)

Russian Communist party activists and supporters carry portraits of Soviet founder Vladimir Lenin (R) and Soviet dictator Josef Stalin (L) as they attend a flowers-laying ceremony at the Lenin's Mausoleum on Red Square in downtown Moscow on November 7, 2021, marking the 104th anniversary of the Bolshevik Revolution also known as the October Revolution. (Photo by Dimitar Dilkoff/AFP Photo)

ESA astronaut Paolo Nespoli looks on after landing back on Earth from their Soyuz TMA-20 spacecraft on May 24, 2011 in Zhezkazgan, Kazakhstan. The mission of the Soyuz TMA-20 was launched last December to the International Space Station with the flight engineers Catherine Coleman from the United States, Russian cosmonaut Dmitry Kondratyev and Italian astronaut Paolo Nespoli. The next expedition is expected to launch this June. (Photo by Stephane Corvaja/ESA via Getty Images)

Russian-born artist Vlad Korneev poses for a picture in his museum called “Designpanoptikum, Museum For Extraordinary Objects” on November 4, 2010 in Berlin, Germany. The museum displays objects whose outward appearance was determined by function rather than form, he says, and are the result of a collection he started while accumulating props for his photographic works. (Photo by Sean Gallup/Getty Images)

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.