St Catherine's Island
|St Catherine's Island|
|Geographical location||51 ° 40 ′ 14 ″ N , 4 ° 41 ′ 30 ″ W|
|Highest elevation||34 m|
St Catherine's Island ( Welsh : Ynys Catrin ) is a small island near the town of Tenby in Pembrokeshire , Wales . The island can be reached on foot via a beach at low tide. A fortress was built on the island in 1869 to prevent attacks towards Pembroke Dock .
The third episode of the fourth season of the BBC series Sherlock , The Final Problem , was filmed largely on the island. The fortress subsequently served as a maximum security prison.
- ↑ Kathryn Williams, Joshua Knapman: Revealed: Sherlock's Sherrinford is Tenby landmark St Catherine's. Retrieved February 14, 2017 .