"The world’s earliest tidal mill dates back to Roman London, on the estuary of the River Fleet. (The oldest remains are in Ireland). Once a broad tidal basin, in Roman times the Fleet was several hundred feet wide." Marilyn Todd
An iron age roundhouse, the protogenor of the broch tower. The experts think this was the most likly roof structure that sat atop of the broch. Archeaology shows posts holes in some brochs meaning these beams would continue from the ground floor to support the roof about the second floor. Also note the artist has included a fire on the ground floor, where did the smoke go???