discuss how and why were stupas built
Answers
Stupas originated as pre-Buddhist tumuli in which śramaṇas were buried in a seated position[3] called chaitya.[4] After the parinirvana of the Buddha, his remains were cremated and the ashes divided and buried under eight mounds with two further mounds encasing the urn and the embers. The earliest archaeological evidence for the presence of Buddhist stupas dates to the late 4th century BCE inIndia. Buddhist scriptures claim that stupas were built at least a century earlier. It is likely that before this time, stupas were built with non-durable materials such as wood, or even as just burial mounds, little is known about these early stupas, particularly since it has not been possible to identify the original ten monuments. However, some later stupas, such as at Sarnath and Sanchi, seem to be embellishments of earlier mounds. The earliest evidence of monastic stupas dates back to the 2nd century BCE. These are stupas that were built within Buddhist monastic complexes. These stupas replicated older stupas made of baked bricks and timber in stone.Sanchi, Sarnath, Amaravati and Bharhut are examples of stupas that were shaped in stone imitating previously existing wooden parts.
The stupa was elaborated as Buddhism spread to other Asian countries becoming, for example, the chörten of Tibet[5] and thepagoda in East Asia.[6] The pagoda has varied forms that also include bell-shaped and pyramidal styles. In the Western context, there is no clear distinction between the stupa and the pagoda. In general, however, "stupa" is used for a Buddhist structure of India or Southeast Asia while "pagoda" refers to a building in East Asia which can be entered and which may be secular in purpose.
Stupas were built in Sri Lanka soon after Devanampiya Tissa of Anuradhapura converted to Buddhism. The first stupa to be built was the Thuparamaya. Later on, many more were built over the years, some like the Jetavanaramaya in Anuradhapura being one of the tallest ancient structures in the world.