[Excuse_My_Bellicosity]

This is interesting. A piece of comet hit Siberia in 1908. It exploded with such force that is flattened miles of forest. I've seen recent pictures that are pretty interesting.

[Mr. Mojo]

I've seen those same pictures on the Discovery Channel --- Tunguska, 1908. No crater was found because the icy comet exploded in the earth's atmosphere before contact with the ground.

[Alberta's Child]

There are a couple of possible ancient meteor craters in eastern Canada. The southeast corner of Hudson Bay has a remarkably circular shape that would indicate a possible impact site, with the Belcher Islands as the "cone" of the crater.

Also, the Manicouagan Reservoir is a peculiar circular body of water surrounding a large land mass that was formed behind the Daniel Johnson Dam in northeastern Quebec.