Up here you'll have one of the best, public-accessible views in all of Kingston. To the west is the steeple of St. Mary's Cathedral. To the east is Lake Ontario and the domes of St. George's Cathedral and City Hall.
Make your way to the top level of the garage. There are several sets of stairs, an elevator at the middle Brock Street entrance, or you can drive up. Cost of parking is 75 cents for the first half hour. Warning though, you may need more than half an hour to find this cache. The good news is that you should have the place pretty much to yourself.