This island wilderness is located within city limits near the mouth of the busy harbor, yet it's a world apart from downtown Halifax. Once part of the city's military defenses and later the site of a popular amusement park, McNab's hasn't had any permanent residents since 1985. Today you'll find miles of wooded roads and trails to explore, some 200 species of birds, and great views of the city skyline and Point Pleasant. The fort at the island's southern tip dates from 1888 -- it was manned during both world wars, when all ships visiting Halifax harbor were required to signal the fort. (Those that failed to comply were warned with a shot across the bow.) Bring a picnic (and a ferry schedule) and plan to spend 2 hours or so.