 After the English Civil War the Royal Citadel was built in 1666 on the east end of Plymouth Hoe , to defend the port from naval attacks , suppress Plymothian Parliamentary leanings and to train the armed forces . Guided tours are available in the summer months . Further west is Smeaton 's Tower , which was built in 1759 as a lighthouse on rocks 14 miles ( 23 km ) off shore , but dismantled and the top two thirds rebuilt on the Hoe in 1877 . It is open to the public and has views over the Plymouth Sound and the city from the lantern room . Plymouth has 20 war memorials of which nine are on The Hoe including : Plymouth Naval Memorial , to remember those killed in World Wars I and II , and the Armada Memorial , to commemorate the defeat of the Spanish Armada . 
