Interesting tidbit about Avebury that I covered a few weeks back, in case you (or our wife) are interested:

Non-descript stones found at Avebury Henge were carried by humans from 280 miles away. Interestingly, these specific stones have only been found at one site. Why the people of this time would take pebbles on their journey is a mystery. Perhaps they simply wanted to bring a piece of home with them, but regardless of why, this discovery speaks to interconnectedness and the amount of travel taking place in ancient times. Summarized from source: https://www.youtube.com/watch?v=RxcY28W3F6M