Thus, the Sacred Tooth Relic became the repository of Sinhala Sovereignty. The “Atadage” the Temple of the Tooth Relic is the most impressive structure among the remains of Polonnaruwa.The Gal Vihara, the Stone Reliquary, with its enormous rock sculptures is undoubtedly one of the greatest achievements of Sinhalese art.Polonnaruwa city is where you can see the island’s greatest historical treasures. It is still of great economic significance as a contributor to agriculture. The enormous reservoir called the Parakrama Samudraya (Sea of Parakrama) was built by King Parakramabahu the 1st (1153-1186 AD).The large expanse of water dominates the entire Citadel of Polonnaruwa and its environs with its retaining wall, 14 kms in length and 12m in height. The manmade reservoir covers a surface area of 15 sq.kms.