The Ruwanwelisaya (Ruwanweliseya Stupa or Ruwanveli Seya Stupa) is a Stupa in Anuradhapura District in North Central Province of Sri Lanka, considered a marvel for its architectural qualities and sacred to many Buddhists all over the World. It was built by the great King Dutugemunu (164 BC – 140 BC), who became lord of all Sri Lanka after a war in which the Chola King Elara, was defeated. The Ruwanweliseya is ranked among the tallest ancient monuments in the World. The Stupa is adjacent to the Jaya Sri Maha Bodhiya in the Mahamevuna Uyana.
The Mahathupa or Ruwanweliseya is known by several other names as well. It is also called Maha Stupa / Mahathupa (the great Dagoba), Rathnamali Stupa / Rathnamali Dagaba, Suvarnamali Mahaceti (in Pali) and Swarnamali Stupa / Swarnamali Chaitya has been the most adored, most venerated among the great ancient Stupas (Dagobas) of Sri Lanka. The name Mahaseya or Mahathupa (the Great Tope) was used in the Golden Age of Anuradhapura.
Ruwanweliseya Stupa is one of the “Solosmasthana”, the 16 sacred religious locations in Sri Lanka and the "Atamasthana" (the 8 places of veneration in the ancient sacred city of Anuradhapura). The Stupa is one of the World's tallest ancient monuments, standing at about 103 m (338 feet with pinnacle; and 278 feet without pinnacle, with chatra) and covering an area over an acre and a half with the diameter of the dome at the base being 290 m (951 feet). The original Stupa had been about 55 m (180 feet) in height and was renovated by many Kings.
Like most Sri Lankan Stupas, the Ruwanweliseya has been built like a bubble floating on water. So, it is said that originally the Stupa was constructed in the Bubble shaped (Bubbulaakara).
Anuradhapura is replete with the ancient cultural monuments located in between the River Malwatu Oya and two great ancient man-made irrigation reservoirs called Tissa Wewa and Abhaya Wewa (Basawakkulama Wewa). These two ancient irrigation reservoirs, together with ancient Nuwara Wewa reservoir on the Eastern flank of the River Malwatu Oya, extend the lifeline to the agricultural district of Anuradhapura.
The three main ancient Stupas clustered South of the ruined Southern wall of Anuradhapura, namely Ruwanweliseya Stupa, Mirisavatiya Dagaba and Jetavana Stupa perfectly align with the celestial layout of Rigel, Mintaka and Bellatrix, three of the seven stars of the Orion constellation, which was associated with Osiris, the Sun-god of rebirth and afterlife, by the ancient Egyptians (3150 BC-conventional Egyptian chronology).