If you like your walks to take in the local history, try the Garrison Walls walk on St Mary's. Now managed by English Heritage, the Garrison Walls is an impressive coastal defence system and a thoroughly enjoyable two-hour walk.
The Brits may have seen off the Spanish Armada in 1588, but they weren't taking any chances. The Governor of the Scillies, Sir Francis Godolphin, was sure that "the gathering of these Spaniards seemeth as a cloud that is like to fall". To protect Scilly's coast from potential future invasions, a fortress (Star Castle) and curtain walls were commissioned on the headland called The Hugh.
The Second Spanish Armada got nowhere near the Scillies; however the defences saw action as a Royalist stronghold during the Civil War, and were later strengthened during the 18th century to defend the coast against French invasion. A lot of the remaining structures date from this period, and as you walk around the walls, you'll see ruined batteries, barracks and stores. Look out for the WWII pillboxes inside the older batteries.
There are information panels along the way that put the ruins into context. If you want to know more, there's an exhibition in the Powder House (just by the main gateway), which is open from 8am until 4:30pm. The site in general is open at "any reasonable time during daylight hours".
Star Castle is now part of a hotel; however, you can take a trip across to Tresco to visit King Charles's Castle, another Tudor fort, or the slightly later Cromwell's Castle. Along with Harry's walls on St Mary's, these form Scilly's impressive defence system, now all cared for by English Heritage.
