Lake Jänisjärvi lies in the Republic of Karelia, about 25 km north of Lake Ladoga. The lake fills a meteorite impact crater about 14 km in diameter, formed roughly 700 million years ago. Seen from space, it is almost oval, about 13 by 17 km across. The meteorite struck ancient schists, melting and crushing the rock. Today impact melt rocks and suevites are exposed on the islands in the middle of the lake and on Cape Leppiniemi on the western shore.
Jänisjärvi is not far from my home city, St. Petersburg — only about 300 km away — and I have been there twice. The goal of the trip was to collect impact rock samples from the island on the right side of the lake and to explore the western and eastern shores. Shatter cone samples were found on the eastern shore.
Coordinates of the Jänisjärvi impact crater: 61°58′N 30°55′E.