The Buddhist Stupa was originally a burial mound for relics of the historical Buddha or other sacred objects. It was topped with a structure similar to the one on the right which is a 2,000 year old miniture stupa from Northwestern India or Pakistan now at the Asian Art Museum in San Francisco.
As the stupa form moved to China and Japan, it evolved into pagodas. This pagoda in San Francisco's Japantown was built 2,000 years after the one on the right and as you can see the top of the pagoda is very similar to the top of the stupa. (I'm getting ready for a presentation this month!)
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