Rob:
Yonaguni Monument is an underwater thing that looks like a manmade monument off of an island coast in southern Japan that hasn't been above sealevel for 8,000 years.
Some scientists say that it just looks manmade and is all naturally formed, some say that it is mostly naturally formed and partially manformed, some say it is a man-made monument. People think it is possibly Atlantis or Mu.
Here's a picture:
