While visiting West Tanfield, take a slight detour to visit the nearby hamlet of Thornborough. In the fields to either side of the road you will be able to see the remains of an archaeological site described by English Heritage as "the most important ancient site between Stonehenge and the Orkneys". It is a ritual landcape containing three henge monuments, a cursus, a double pit alignment and several round barrows, representing human construction on the site in the Neolithic and Bronze age period. There are no doubt other features to be discovered, however the landscape has already been disturbed and is under further threat from extensive quarrying. (If you want to help preserve the monuments there is a petition being signed)
If you visit the Timewatch site, when the animation gets to 2000BC, you will see the outline of the linear post alignment that I worked on when I volunteered there in 1999. Those dots represent postholes, each of which was about a metre across!