Explanation:

The Great Stupa at Sanchi is one of the oldest stone structures in India, and an important monument of Indian Architecture. It was originally commissioned by the emperor Ashoka in the 3rd century BCE. Its nucleus was a simple hemispherical brick structure built over the relics of the Buddha. It was crowned by the chhatri, a parasol-like structure symbolising high rank, which was intended to honour and shelter the relics. The original construction work of this stupa was overseen by Ashoka, whose wife Devi was the daughter of a merchant of nearby Vidisha. Sanchi was also her birthplace as well as the venue of her and Ashoka's wedding. In the 1st century BCE, four elaborately carved toranas (ornamental gateways) and a balustrade encircling the entire structure were added. The Sanchi Stupa built during Mauryan period was made of bricks. The composite flourished until the 11th century.