text:  I'm in the middle row of a minivan barreling down I-295 in D.C. We pull over onto the shoulder of the freeway near the city's southern border. The other passengers laugh. There's no destination in sight. Our guide, Steven Powers, leads the way into overgrown woods. It's a little trickier because they replaced the fence. There was a hole in the fence that we went through, but they replaced that.