Walking around Mirror Lake, which just borders the main street of the town of Lake Placid, can be a great experience. The lake is small enough to make this possible, yet large enough for it to be a good exercise. Walking at a reasonable pace (not necessarily strenuous or hurried), you can complete the circuit in about one hour. You'll appreciate the beautiful view, get to know the vicinity better, and be greeted by several other people of all ages doing the same walk.