There's this really sweet place in Claremont NH about a mile west of the Boston And Main Rail Road if you follow the Claremont And Concord line into town. It's a little bit down and behind the old AMES Plaza. Walk on the tracks until you can see a stream about 50 to 70 feet down below, and then just walk down the hill to the stream. A dual tunnel allows the stream to go underneath the Rail Road, which is a manmade hill that spans the ravine created by the streams. It must be at least 125 to 200 feet long. It's very difficult to guess. Almost no light can get in, other than the light at the end of the tunnel! Even in the most torrid summer dryness, the tunnels have bursty cool mist at all times -- the ravine creates a forced wind tunnel, and the water keeps things at 100% humidity. This, and the fact that it is essentially underground, makes this spot probably my favorite place to be ourdoors.