It took researches 30 years of drilling through a four-kilometer-thick ice to reach the renowned subglacial lake. Most importantly, million years-old secrets will be unveiled without causing harm to the lake's ecosystem. "2/5/2012 our scientists at the Vostok polar station in the Antarctic completed drilling at depths of 3,768 meters and reached surface of the subglacial lake," RIA Novosti quoted unnamed Russian scientist. Lake Vostok is a unique aquatic ecosystem hidden under some four kilometers of ice. Its water has been isolated from the atmosphere -- and therefore from the outer biosphere -- for millions of years. Scientists believe that surveys of the lake can provide invaluable details on past and future climate changes.