Women jump into the water during a traditional New Year bath in the Adriatic sea in Portoroz, Slovenia on January 1, 2018. (Photo by Jure Makovec/AFP Photo)

Dancers from the McLoughlin school in Glasgow, Scotland put on make-up as they get ready to participate in the 2022 World Irish Dancing Championships on its 50th anniversary, in Belfast, Northern Ireland on April 14, 2022. (Photo by Clodagh Kilcoyne/Reuters)

A juvenile blackcap is recorded in the soft light of morning at Minorca, UK, a former open-cast mine near Moira in the National Forest on June 18, 2025. Dr Heather Gilbert, research and evidence manager, checks mist nets among wildflowers and young trees as part of long-term monitoring that shows bird numbers have increased by 48 per cent over 30 years. (Photo by Rod Kirkpatrick/RKP Photography)

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.

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)

Actress Oh In-Hae and director Ahn Sang-Su arrives for the opening ceremony of the 16th Busan International Film Festival (BIFF) during the press conference at the Busan Cinema Center on October 6, 2011 in Busan, South Korea. The biggest film festival in Asia showcases 307 films from 70 countries and runs from October 6-14. (Photo by Chung Sung-Jun/Getty Images)

The Zhangjiajie National Forest Park is a unique national forest park located in Zhangjiajie City in northern Hunan Province in the People's Republic of China. It is one of several national parks within the Wulingyuan Scenic Area.