Short answers, pulled from the story.
Lake Onega emerged from the retreat of inland ice sheets about 12,000 years ago. This geological event carved out a basin that had once been covered by a shelf sea during the Paleozoic Era.
Lake Onega stretches with a surface area of roughly 97,000 square kilometers without islands. It holds a volume of approximately 1,300 cubic kilometers and ranks as the second largest lake in Europe.
Eastern shores hold about 1,200 petroglyphs carved between the 4th and 2nd millennia BC. These rock engravings cover an area of roughly 3 square kilometers on several capes including Besov Nos.
Cargo transport moves 10 to 12 million tonnes per year through ports at Petrozavodsk and Medvezhyegorsk. Metallurgy production in Petrozavodsk accounts for about 25% of all industrial products in Karelia.
The petroglyphs received UNESCO inscription in 2021 for their significant artistic qualities. The island hosts a historical complex containing 89 Orthodox churches and wooden structures dating from the 15th to 20th centuries.