The 54m Rankot Vihara dagoba, the largest in Polonnaruwa and the fourth largest on the island, has been ascribed to the reign of King Nissanka Malla. Like the other major dagobas in Anuradhapura and Polonnaruwa, the dome consists of earth fill covered by a brick mantle and plaster. The construction clearly imitates the Anuradhapura style. Surgical instruments found in a nearby ruined 12th-century hospital are surprisingly similar to those used today; see examples in the Archaeological Museum.