Belle Isle has had a storied past: native American village, Civil War POW camp, horse track, and industrial site. Now, it's a public park with many elements from its historic past... making it one of Richmond's most intriguing sites.
This 54-acre expanse has always been there, but was made more accessible with the construction of a downtown pedestrian bridge about 10 years ago. To get there, you'll walk it--suspended above the raging Hollywood Rapids, and dangling from the interstate above. It sounds quite treacherous, but it's not.
Once you're there, follow the path that heads south (parallel to the overpass). You'll pass (and be able to wander through) remnants of the park's industrial past: stone walls, steel frames, and even an entire hydroelectric plant. The ruins are what make Belle Isle truly unique; in an era of high liability, it's one of the few sites where you can legally wander through such abandonment.
The trail leads around to the Rapids and past other vestiges of its life as a POW camp. Earthen mounds and defensive positions have worn down over time, but they're still there.
Do be prepared to walk over some rugged terrain, especially if you opt to climb the hill in the center of the island. Wade out into the water at your own risk, since the Rapids are deceptively strong. And be sure to visit the bathroom before hitting the island, since bathroom facilities aren't available.
Belle Isle is located across the James River from Tredegar Iron Works. To get there from downtown, go south on 5th Street, and hang a right when the road ends. Free parking is on your right, under the railroad trestle and before the Ethyl Corporation parking lot.