This is a cave inside of the Colorado side of Dinosaur National Monument. On the summer day we visited, the air inside was cool, even though feet away, at the opening, the temperature skyrocketed to the high 90s. The cave is rather unique because on either side of the central rock are slots that go straight up. I’m not sure how far they reach, but it is far enough. This is where the cold air comes from. If you want to visit, head towards the Echo Park Campground inside the Monument. The cave is about a mile before you arrive at the campground, on the right hand side of the gravel road.