Standing sentinel over Saint Peter Port for over 800 years, this wonderfully intact castle has been a major player in every historical event to affect the island, from the French sieges and the Napoleonic wars to the Civil War and WWII. The maze of courtyards, towers, passageways and keeps is a joy to explore and there are five museums on-site, the best being the Maritime Museum and the Story of Castle Cornet.
At the Maritime Museum, look out for amphorae and coins dating back to the Roman trade, goods traded after the Norman conquest and when Guernsey was a haven for pirates and privateers, and artistic renditions of dramatic rescues carried out by modern-day Guernsey lifeboats.