I am a big fan of history.
Don't get me wrong, I like living in Calgary, but it does not have the history, buildings, etc, you find on the coast.
Halifax was founded in 1749, Dartmouth 1750.
If you are a history buff at all here is a quick read on the Halifax explosion. Ocurring during the 1ST World War, it is/was the largest pre-Atomic man made explosion.
http://museum.gov.ns.ca/mma/AtoZ/HalExpl.html
You will be standing in the area where the events unfolded. The only reason that some of the old buildings you will see are still there is that the blast wave went over top of them.
Jaun came through in 2003, couple of pictures