Coming October 16, 2016. One of the few marathons with a transnational course. The Detroit Free Press/Talmer Bank Marathon takes you from the Motor City over the Ambassador Bridge into Windsor, Ontario, Canada and returns via the Detroit-Windsor Tunnel. A fun fact about this course is that it has the only official underwater international mile in the world, as the Detroit-Windsor Tunnel runs underneath the Detroit River. It takes place in the fall, but the registration is capped at only 5,500, so you might want to sign up now and make sure your passport is valid!