Vatadage

The Vatadage ( hale of the relic) near the entrance is a circular building with a dageba on concentric terraces with sculptured railings, the largest with a diameter of 18m. A superbly planned and executed 12th century masterpiece attributed to Naissankamalla (1187-1196), the Vatadage has modest proportions but remarkably graceful lines. It was almost certainly intended to house the Tooth Relic. There are impressive guard stones at the entrance of the second terrace and wing stones with makaras enclosing lion figures; the moonstone to the north entrance of the top terrace is superb. The dagaba at the center has four Buddha's (some damaged) with later stone screen.
The Vatadage is circular building on your left as you enter - is probably the oldest monument in Polonnaruwa, preceding by several centuries the establishment of the capital.
At the building's northern entrance is a guard stone (one of a former pair) preventing evil from entering. The moonstone at the second flight of steps is the best preserved in Polonnaruwa. In the center of Vatadage, within the concentric stone columns that once supported a conical roof, four Buddha status face the cardinal points, their backs to the sacred mound of brick all that remains of the dagaba

see : www.amazinglanka.com/pollonnaruwa/vatadage/vatadage.php