Harborside Halifax is the biggest city in the Maritime Provinces by far, yet it doesn't feel big at all -- in just the way that Boston and San Francisco don't feel like huge cities. It actually feels like a collection of loosely connected neighborhoods, which is in fact what it is; you often forget this is one of the central economic engines of eastern Canada.
Established in 1749, the city was named for George Montagu Dunk, second earl of Halifax. (Residents agree it was a huge stroke of luck that the city avoided being named Dunk, Nova Scotia.) The city plodded along as a colonial backwater for the better part of a century, superceded by nearby towns building more boats (Shelburne and Lunenberg, to name two); one historian even wrote of Halifax as "a rather degenerate little seaport town."
But the city's natural advantages -- that well-protected harbor, its location near major fishing grounds and shipping lanes -- eventually caused Halifax to overtake its rivals and emerge as an industrial port and military base for the ages. Relatively speaking, of course. And then, at long last, so came the tourists and scholars and urban escapees from Toronto: In recent decades, this city has grown aggressively (it annexed several adjacent suburbs in 1969) and carved out a niche for itself as the commercial and financial hub of the Maritimes.
Today it's also the cultural cutting edge of eastern Canada, for what that's worth. Pop singer Sarah MacLachlan grew up here, and it's also the hometown of professional hockey's "next Gretzky," young Sidney Crosby of the Pittsburgh Penguins -- and that's a big deal in hockey-crazed Canada. (Crosby's 2009 victory parade with the Stanley Cup snarled downtown's streets, but nobody complained.) So long as you're not allergic to beer, good food, ocean breezes, and good music, I think it's fair to say you'll never be at a loss for something to do during your time here.