A Guarani boy pets a puppy in the Mata Verde Bonita village, in Marica, Rio de Janeiro state, Brazil, Thursday, February 25, 2020, where healthcare workers are making the rounds with coolers containing doses of China's Sinovac COVID-19 vaccine as part of a mass immunization program aimed at inoculating all of Rio's 16 million residents by the end of the year. (Photo by Bruna Prado/AP Photo)

A handout picture taken and released by the British Ministry of Defence (MOD) on March 25, 2024 shows humanitarian aid being airdropped over Gaza from a RAF A400M aircraft The Royal Air Force airdropped over 10 tonnes of food supplies into Gaza for the first time on Monday, as part of international efforts to provide life-saving assistance to civilians. The aid consists of water, rice, cooking oil, flour, tinned goods and baby formula. (Photo by Leah Jones/MOD/AFP Photo)

Members of the Sydney Swans Football Club and LA Rams cheerleaders walk in the Sydney Gay & Lesbian Mardi Gras Parade as part of Sydney WorldPride on February 25, 2023 in Sydney, Australia. The Sydney Gay and Lesbian Mardi Gras parade returns to Oxford Street in celebration of the event's 45th anniversary. The parade began in 1978 as a march to commemorate the 1969 Stonewall Riots in New York and has been held every year since to promote awareness of gay, lesbian, bisexual and transgendered issues. (Photo by Brendon Thorne/Getty Images)

The 26-foot-tall “Forever Marilyn” statue, was hoisted by crane early this morning in downtown Palm Springs, California on February 25, 2025. This larger-than-life tribute to Monroe's iconic pose from “The Seven Year Itch” is being moved to resolve ongoing legal disputes over its placement. Installed in 2021 near the Palm Springs Art Museum, the statue faced criticism and legal challenges regarding public access and aesthetic concerns. (Photo by Ian L. Sitren/ZUMA Press Wire/Rex Features/Shutterstock)

A sick California sea lion with possible domoic acid poisoning is rescued to be evaluated by volunteers from CIMWI (Channel Islands Marine & Wildlife Institute) in Santa Barbara, California, on March 25, 2025. Over a hundred sea lions, dolphins and other marine mammals, including birds, have been sickened by domoic acid poisoning from algal blooms in Southern California since February, US media reported. (Photo by David Swanson/AFP Photo)

Philippine actor Soliman Cruz wearing a business suit stands inside an 8-foot transparent bubble while other activists wearing masks touch the bubble during an anti-pollution protest near a park in Manila on April 25, 2025. The protest is part of a climate advocates 350 campaign on Manila's air pollution crisis, due to traffic emissions, fossil fuel and unchecked industrial activity. (Photo by Ted Aljibe/AFP Photo)

A man reacts as he holds the equipment used by Palestinian cameraman Hussam al-Masri, who was a contractor for Reuters, at the site where he was killed along with other journalists and people in Israeli strikes on Nasser hospital, in Khan Younis in the southern Gaza Strip, in this still image taken from a video shot by Reuters contractor Hatem Khaled, who was wounded shortly afterwards in another strike while he was filming the site on August 25, 2025. (Photo by Hatem Khaled/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.