National parks tend to get the spotlight, but some of the most quietly powerful places I’ve visited don’t carry that designation at all. A monument marking a single battlefield. A fort that once held a frontier. A missile silo that could have changed the course of history but never had to.

Wherever these sites fall along a park route, I try to make room for them — Bent’s Old Fort, Little Bighorn, Devils Tower, Fort Laramie, the Klondike Gold Rush district, the memorials lining the National Mall, and dozens of others in between. This collection is where those stops will live: the places that don’t always make the itinerary, but often end up being the ones I remember most.