Broch of Mousa, Shetland
This is an Iron Age style broch, which was built round about 100 BC and it the tallest of all brochs, as it still preserves its full structure, save the (likely thatched) roof. In fact, it is one of the best-preserved prehistoric buildings of Europe. It is situated on the Island of Mousa, which is now uninhabited, and it can only be reached by boat, which operates between April and September. Storm petrels, European shags and seals can be seen on the island, as well as, a beautiful rugged coastline.
You can see more of the island here.
A tour of Mousa Broch on my Youtube channel.
Island of Mousa, Shetland
This is a small uninhabited island, which mainly serves as a nature reserve. There you can also find the Broch of Mousa, which is preserved almost in its entirety. The Mousa Boat takes you across for a few hours from April to September, before the stormy winter season begins. We were able to watch birds and seals from the distance and enjoyed the circular walk along the beautiful cliffs before the boat took us back to the mainland of Shetland.
Here you can see Mousa Broch up close.
My Youtube video about the trip to the Island of Mousa.