In 40 minutes, you can be out of the city and working your way through a tree-covered hillside. The three-mile loop hits you with a steep ascent to start before rewarding you with carveouts that offer spectacular views of the Meramec River curling along below. Even if you just parked on one of the benches up there, ate a snack and walked back down, it would be a nice morning. But if you crest the peak, you'll enjoy picking your way down the backside alongside the ruined staircase of long-gone resorts before slipping through a tunnel in a railroad trestle. From there, it's a pleasant (and flat) walk along the river's edge, passing massive, gnarled trees and more old ruins from the area's party-haven past. This lowland part of the trail also includes great birding habitat. The loop eventually swings you around back to the park's wide fields and parking lots. It can get busy in nice weather, but come early and you're almost guaranteed to be rewarded with a quieter trail and wildlife sightings.