Perched atop the grassy hillock looming over town, this star-shaped fort played a key role in Halifax's founding. Construction began in 1749; the current citadel is the fourth, built from 1818 to 1861. The grounds and battlements inside the fort are open year-round, with free admission when the exhibits are closed, but it's better to come between May and October, when you can visit the barracks, the guards' room, the signal post, the engineer's store and the gunpowder magazines.
Between May and October there's a variety of extra activities on offer, including informative guided tours explaining the fort's shape and history, spooky ghost tours (adult/child $14/8), the chance to dress up as a soldier for the day ($199), and even the chance to fire three rounds from a Snider-Enfield rifle ($22).