Aceleradora is a therapy unit built on a terrace at La Paz Hospital in Madrid. It is part of a reserach project of the Unoentrecienmil Foundation that studies the impact of physical exercise on the recovery of children and teenagers with cancer. It is the first of a series of units to be built in diferent hospitals. This is the reason why it was conceived as a modular system. The various prfabricated modules were built off-site and assembled on the roof during a single night