The Rock Circuit Trail is deceptively tricky with several rock scrambles, although some are optional. We did not budget enough time and ended up getting back to the car in the dark. The views along the rocks were great, however, and we saw several different types of wildlife. In addition to an insane amount of caterpillars, we also saw a fox scamper across the trail, an owl take flight, a rabbit chilling in some grass, a bird of prey take on a smaller songbird, and a hawk on a branch above us. Cascade Falls is a surprisingly tall waterfall for the Boston area, and the MIT Observatory Site includes an info board with some history of the place.