Features of stupa architecture:

• Generally, there is a small box placed at the centre or heart of the stupa. This may contain bodily remains of the Buddha or his followers, or things they used, as well as precious stones, and coins.
• Often, a path, known as the pradakshina patha, was laid around the stupa. This was surrounded with railings.
• Entrance to the path was through gateways.
• Both railings and gateways were often decorated with sculpture.