Underneath a battle shrine where Filipinos took a stand against Spanish colonial rule lies one of the largest underground reservoirs in the world. Made of volcanic tuff, the underground reservoir held water carried over the waterworks system from the Marikina River before being distributed to various fountains and hydrants in Manila. It was part of the larger Carriedo waterworks designed by Genaro Palacios and built from 1878 to 1882. The infrastructure project was named after Francisco Carriedo y Peredo, a Spanish official who bequeathed a grant to the City of…
