To the east of the Cultural Triangle, following the Anuradhapura era is the second ancient capital of Sri Lanka, Polonnaruwa. The Polonnaruwa legacy may have lasted for only two centuries however judging by the colossal monuments and monasteries it left behind it is clear that it was dynasty that cannot be easily forgotten. The archaeology remains at Polonnaruwa are exhibited at the Museum of the Central Cultural Fund and its visitor centre. It was King Vijayabahu I who defeated the Chola invaders and regained its land after 52 years. Since then Vijayabahu devoted his long reign to the restoration of the country. However Polonnaruwa is largely King Parakramabahu’s city. He built walls that would surround the city and further strengthened the fortifications of its inner city. The great Parakramabahu tank was built after he linked up and expanded three former tanks of Polonnaruwa,

The Rajanganaya Dam (also sometimes called Rajangana) is an irrigation dam built across the Kala Oya river, at Rajanganaya, bordering the North Western and North Central provinces of Sri Lanka. The main concrete dam measures approximately 350 m (1,150 ft) and creates the Rajanganaya Reservoir, which has a catchment area of 76,863.60 hectares and a total storage capacity of 100.37 million cubic metres