Tunguska Event Crater Site
In response to Ace:
Back in 2007 a scientific journal published a paper suggesting that Lake Cheko may have been the impact site for whatever exploded over Tunguska in 1908. As the abstract explains "Its funnel-like bottom morphology and the structure of its sedimentary
deposits, revealed by acoustic imagery and direct sampling, all suggest
that the lake fills an impact crater." The lake is 50 meters deep which is unusual for the area.
After getting interested in this I put together a Google map featuring 22 large impact sites around the world including Lake Cheko.
I had a lot of time on my hands in 2007.