I don't know much about cones, but here is what Google said.
Answer:
Stupa, Buddhist commemorative monument usually housing sacred relics associated with the Buddha or other saintly persons. The hemispherical form of the stupa appears to have derived from pre-Buddhist burial mounds in India.
Explanation:
The stupa (“stupa” is Sanskrit for heap) is an important form of Buddhist architecture, though it predates Buddhism. It is generally considered to be a sepulchral monument—a place of burial or a receptacle for religious objects. At its simplest, a stupa is a dirt burial mound faced with stone.
