Built in the 1st-century under the reign of King Aggabodhi I, and used by the bhikkhus of Abhayagiri monastery, these twin granite ponds lying head to head represent the amazing architectural and engineering skills of ancient Sri Lankan people. Two two ponds are connected with conduits laid underground. There are ruins of four filtering chambers which are connected to the pond by conduits. Filtered water falls in the pond through a dragon’s mouth carved into granite rock.
The two ponds vary in length but share a similar width, larger pond is 132 feet by 51 feet with a depts of 18 feets while the smaller pond is 91 feet by 51 feet with a depth of 14 feets. The ponds were built with perfectly cut granite slabs. On the two ends are steps to climb into the ponds with punkalas (pots of abundance) decorations. The pond also has amazing carvings of a five hooded naga (cobra king with five heads) stone.