There's more monkey in kids than we realise. Leave them to their own devices at the new CityROCK climbing gym and before you know it they're up the wall, bending and flexing their limbs into the impossibly supple positions of youth. Harnesses are on hand at the entrance of the cavernous space filled with hundreds of routes of varying difficulty, in hired climbing shoes they'd rather not wear, they hit those walls as if auditioning for Mission Impossible.Thick mattresses at the base of each climb make short falls comfortable so kids can climb low walls without hooking up to a climbing rope.If they want to go vertical they attach themselves to automatic belay devices so they can climb without a parent holding a rope.But grown-ups are kids too at CityROCK, although they climb with looks of extreme exertion instead of smiles on their faces.Choruses of ''on belay", ''belay on", ''climbing" echo around the room as teams of two take turns to hold ropes and abseil.Routes are numbered and graded for difficulty and there's nothing quite as satisfying as advancing a grade or two over a climbing session.The 1500m2 of high climbing terrain that reaches up to 16 metres high means you can spend as many hours as your level will allow, before your muscles are weak with exhaustion. CityROCK has 100 top ropes, grade 12-26 and 80 lead routes, from grade 15 to 30. There are 230m2 with child and beginner climbing and boulder terrain with 15 top ropes, five automatic belays and 600m2 of terrain, with boulders up to 4.4m high. Plenty of reasons to discover your inner monkey.The gym also offers yoga, cardio, weights and fitness classes, a coffee shop and a great climbing gear shop. 173 Republic Road, Fountainbleau, Randburg, 010-007-2732..