Baikal's underwater telescope hunts cosmic secrets
6 December 2010 Last updated at 18:18 GMT
The Baikal underwater telescope NT-200 in Russia has been set up to capture elusive neutrino particles in a bid to unravel the secrets of the formation of the Universe.
At 0.7 miles (1.1km) beneath the surface of the world's deepest lake and pointing towards the centre of the Earth, it is one of the most unusual telescopes on the planet.
Katia Moskvitch reports.