I participated in a tour of this very antique place, given by members of a foundation called Para la naturaleza, who are trying to preserve places like this one, that not many people know about, but they are filled with history.... OUR history, and this one is so close, and SO IGNORED!!! This facility was built by the Spaniards in order to distribute fresh water from the "Rio Piedras" (in case you also didn't know, there is a river by this name, and it still goes through many areas here in San Juan) to ALL of San Juan! I'm not going to explain the whole tour, because I believe many should find out for themselves....To my amazement, all of this is just a very small distance from all residents in San Juan metropolitan area.....This is within the Botanical Gardens ( Jardin Botánico) and it is free! They only ask for a donation ( whatever you can give) for this fund, in order to continue protecting this, and other similar places in different parts of our island ......