The Ruwanweli Maha Seya, also known as the Mahathupa is a stupa in Anuradhapura, Sri Lanka. Two quarts or one Dona of the Buddha's relics are enshrined in the stupa, making it the largest collection of his relics anywhere. It was built by Sinhalese King Dutugemunu in c. 140 B.C., who became king of Sri Lanka after a war in which the Chola King Elāra was defeated. It is also known as Swarnamali Seya, Svaṇṇamāli Mahaceti and Rathnamali Seya.
This is one of the "Solosmasthana" and the "Atamasthana". The stupa is one of the world's tallest ancient monuments, standing at 103 m and with a circumference of 290 m.
Wikipedia https://en.wikipedia.org/wiki/Ruwanwelisaya
Coordinates 8°21'0.129" N 80°23'47.018" E