Petra Cliffs Climbing and Mountaineering Center is an indoor rock climbing gym in Burlington, Vermont. Spend the day rock climbing and get a good workout! For about $25 (or less if you have your own gear) you can get a belay lesson and go off and climb for as long as you want. You should go with a friend so that you have someone to belay for you, and bringing a bottle of water and comfortable pants or long shorts.