Toronto, Ontario
Although we've found that it's hard to get to some national parks in the USA, such as Yosemite and Death Valley, it was thankfully much easier to get to Niagara Falls on the Greyhound, with the falls being only a two hour journey from Toronto. What better excuse, then, to sample another country and get another passport stamp to add to the collection.
First we had to tear ourselves away from Chicago, which left us wishing that we had planned to spend a week there...