When the Sinhalese kings rebuilt their capital at Polonnaruwa in the 10th century CE, they produced some of the finest architecture and sculpture in Sri Lankan history alongside one of the ancient world’s great irrigation achievements. The Gal Vihara’s four colossal Buddha figures – carved from a single granite face with compositional mastery that reflects both Theravada theology and Mahayana aesthetics – are the period’s finest artistic statement. The Parakrama Samudra reservoir, still a working irrigation system 800 years after its construction, is the pragmatic achievement that runs alongside the spiritual ones.