This stupa belongs to Ramakele Mahanaga Pabbatha Viharaya in Sigiriya. This has been also identified as Mahanapaw Viharaya in the Sigiri graffiti and on a inscription nearby. This stupa is thought to be constructed by king Kashapa I (477-495 AD) or Mugalan I (495-512 AD).
The relic chamber of the stupa was already attacked by treasure hunters when it was discovered and whatever the relics were stolen. It is believed that this stupa would have housed very important relics as the relic chamber of this stupa was uniquely built. The chamber was of 3 compartments with the bottom compartment housing a profusely carved stone replica of "Maha Meru Parwathaya", a mythical mountain. This replica is now housed in the National Museum in Colombo.
What remains on the stupa today is only part of the bubble shaped body with three circular pesa walau. The diameter of the stupa is 92 feet.
Primary Source : "Sri Lankave Purana Stupa"
February 17, 2007