Broch of Mousa - Credit: Wikimedia Commons
Broch of Mousa (or Mousa Broch) is a preserved Iron Age broch or round tower. It is on the island of Mousa in Shetland, Scotland. It is the tallest broch still standing and amongst the best-preserved prehistoric buildings in Europe. It is thought to have been constructed , and is one of more than 500 brochs built in Scotland. The site is managed by Historic Environment Scotland as a scheduled monument. Read more on Wikipedia
Source: en.wikipedia.org