In the Missouri Breaks of Montana, paddling into the past.

It’s a cliche to say that trips through the canyonlands of the West are “journeys through time,” but it’s true. What’s less obvious is that if you pick the right place, you don’t just confront epochs like the Cretaceous, but also more recent and troubling ones. The 149-mile-long Upper Missouri River Breaks National Monument is such a place. It teaches not only geology, but also the part of American history once called “the settling of the West” — a time of heroism and enterprise, as well as perfidy and cultural annihilation.