Jazmin, 6, sister of Jose Luis, receives Isoniazid Preventive Therapy in Carabayllo in Lima, Peru July 14, 2016. At least 30,000 Peruvians are infected with tuberculosis, an ancient disease that killed 1.8 million globally last year, more than AIDS-related and malaria deaths combined. Partners in Health, a Boston-based non-profit that works with Peru's health ministry, offers a simple solution. It trains community volunteers to tend to tuberculosis sufferers in their homes – ensuring patients take medicine daily and helping them navigate the public health bureaucracy. (Photo by Mariana Bazo/Reuters)

A BASE jumper is pictured against the skyline shrouded in a thick haze during the Kuala Lumpur Tower International Jump in Kuala Lumpur, Malaysia, 02 October 2015. More than 100 BASE jumpers take part in this extreme sport event, which enters its 15th year. The haze hovering over Malaysia is caused by the ongoing plantation and forest fires in the nearby Indonesian provinces of Sumatra and Kalimantan. (Photo by Fazry Ismail/EPA)

Iran's Hanieh Rajabi performs during the women's Daoshu competition at the 13th Wushu World Championships in Jakarta, Indonesia, Monday, November 16, 2015. (Photo by Tatan Syuflana/AP Photo)

Kamo Mphela, a South African dancer and singer performs Amapiano, a South African musical export that has crossed borders and cultural barriers, reaching as far as Japan, during a music concert in Pretoria, South Africa, July 22, 2022. (Photo by Shafiek Tassiem/Reuters)

A woman carries a heavy load on her head while walking along the narrow Kilo ZeroKilo 30 road near Bentiu in Unity State, South Sudan, on November 6, 2025. The eroded and flood-affected road compels residents to travel long distances on foot to access supplies in Bentiu and Rubkona. (Photo by Rian Cope/AFP Photo)

A view of electricity wires, in Caracas, Venezuela, 03 April 2019. West Venezuela started receiving electricity intermittently in the states of Zulia, Falcon, Merida and Trujillo after 100 hours without power. (Photo by Miguel Gutierrez/EPA/EFE/Rex Features/Shutterstock)

Miss India Manushi Chhilar (C) reacts as she wins the 67 th Miss World contest final next to France Aurore Andrée Raphaëlle Kichenin (R) and Miss Kenya Magline Jeruto (L) in Sanya, on the tropical Chinese island of Hainan on November 18, 2017. (Photo by Nicolas Asfouri/AFP Photo)

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.