by territorial soldiers during the First World War and additional defences were constructed on the landward side. It continued to defend the harbour and was also used for training purposes. After the war, Pendennis continued to be used for training gunners, but its 16th-century buildings were placed into the guardianship of the Ministry of Works in 1920, and by 1939 the fortification's artillery had all been removed. The castle was rearmed at the beginning of the Second World War. Twin 6-pounder guns and longer range artillery were installed, zig-zag trenches dug for protection, and new buildings added across the site. The 16th-century fort was used as the headquarters of Falmouth Fire Command, which managed the artillery across the area. New radar-controlled, 6-inch (152 mm) Mark 24 guns followed in 1943. Falmouth played an important role in supporting the D-Day invasion of France in 1944, and during the preparations for the invasion, the gun batteries at Pendennis were used to defend against German E-boats. After the war, Pendennis was initially still used for training, but the castle was now obsolete and it was decommissioned in 1956. The whole of the Pendennis site was placed in the guardianship of the Ministry of Works and opened to visitors; the Ministry focused its attention on the 16th-century castle and many of the more modern buildings were destroyed. The barracks were used as a youth hostel between 1963 and 2000. The heritage agency English Heritage took over control of the castle in 1984, and placed a greater priority on the conservation of its more modern features. Extensive work was carried out across the castle in the 1990s to refurbish the fortifications and open new facilities for visitors, accompanied by archaeological surveys and excavations; in the 2000s, the sergeant's mess and the custodian's house were converted into holiday cottages. In the 21st century, the castle is managed by English Heritage as a tourist attraction, receiving 74,230 visitors in 2011–12. It is protected under UK law as a Grade I listed building and as a scheduled monument. Architecture Pendennis Castle is located at the end of a peninsula, overlooking Carrick Roads and the sea. It includes the original 16th-century Device Fort, surrounded by a ring of outer defences, based on the Elizabethan ramparts and later adapted during the 18th, 19th and 20th centuries. Further gun batteries and a blockhouse are located closer to the shore. The heritage