Sarnath is one of the three holiest places of Buddhism. Buddhist from around the world make a pilgrimage here to give their respect to his ideas and philosophy. The stupa marks the location where Buddha, the previous Prince Siddhartha, gave his first sermon in the deer park about 500 bce. A stupa is frequently a reliquary of a remnant of Buddha, a fingernail, ashes, or a bone. As many as 25,000 stupas were created by the children of Chandra Gupta after his conversion to Buddhism about 300 bce. From educational monasteries like the one here at Sarnath until about 300 ce Buddhism spread its way across Asia .