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Photo: via Wikimedia Commons, Public domain
A meteor impact crater, now a lake that forms a nearly perfect circle.
Karikkoselkä is a lake formed in an impact crater in Petäjävesi, Finland. Karikkoselkä is located in Central Finland approximately 30 km east of the centre of Keurusselkä, a much older and larger impact crater. Most lakes in the region are elongated in a northwest–southeast direction due to glaciation, but Karikkoselkä is strikingly round.
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