A group of scientists used sonar to search for shipwrecks at the bottom of Lake Michigan (Michigan, USA). What they discovered was quite surprising. At the bottom of the lake, they discovered a stone structure, which in many ways resembles the famous English Stonehange. However, this is located in the US and in addition 12 meters underwater. Some stones are arranged in a circle. On others, reliefs of the mastodon, which is a variation on the prehistoric mammoth, appear to be visible.

Official archaeologists estimate that the building could be 10000 years old, which in practice means it will actually be older, as it had to be built in the house before Lake Michigan was created. Again, there is a time sometime before the Great Flood 11000 years BC, or just after the last ice age, or rather further before the last ice age.

It is also worth noting that many other stones described by petroglyphs have been found around Lake Michigan.