One day I would love to see Skara Brae in Northern Scotland. There are these incredible stone structures built underground by very skilled, intelligent stone age folks. I've only seen pictures, but the dwellings have a place for a fire, benches, things one would see in a simple home, all made of stone. They are beautiful in their precision. It's by the sea. Think what beautiful man made stone structures could be in the sea now. Would they be intact? I'll see if I can find a photo and post.
It was discovered about 1850, under grass & soil. What makes it so unique is how well preserved the site was. Here are some pics: (note Neolithic, c. 3100-2500 BC) The 1st is a map of how it would have looked during this period. The 2nd is how is looks today. (just a part of it)