Spend hours exploring the underground tunnels, command-posts, munitions rooms, etc.
HISTORY: Stony Batter (named for the large boulders that litter the slopes) was built during the Second World War, part of a top-secret defensive shield against German and Japanese attack. Its big 9.2-inch (234mm) guns, capable of hurling 172kg high-explosive shells up to 32km, could have routed any naval invader. Although the guns were cut up for scrap in the 1960s, the huge gun-emplacements and extensive underground fort