Underworld - Flooded Kingdoms Of The Ice Age

 Graham Hancock's mind bending series on underwater civilisations, lost to humanity after being buried by the great floods at the end of the Ice Age. In the third and final part Graham travels to Yonaguni, an island off Japan, where strange symmetrical structures under water point to the possibility of a lost city. There's also a look at the incredible culture of the Jomon, who made sophisticated pottery at a time when they were considered by academics to be a primitive hunter-gatherer population.

http://youtu.be/RvHD-oLT-qE