Some of the most mysterious ancient ... sites are accessible to the public but best viewed from aircraft. Discovered in downtown Miami, this perfectly circular structure known as the Miami Circle ...

But scientists now believe that the famous Wiltshire stone circle ... ancient enclosure might have been a 'prototype' for later monuments like Stonehenge. Because of the similarity between the two ...

Stonehenge is perhaps Britain's most famous historic site, a place that escapes archaeologists ... people dug out such giant holes in a perfect circle around Stonehenge and Durrington Walls.