Describe in detail the architecture of the stupas.

The word stupa is originated from the Sanskrit word ‘heap’. The initial structure of the stupas was in the shape of simple, semi-circular mound of earth which came to be known as anda. Later this simple structure of the stupa evolved and become complex which balances round and square structures. Above the structure of anda was another structure known as harmika. Harmika was a structure in the shape of the balcony that became the symbol of representation of the abode of God. From the Harmika, a mast like structure arises which came to be known as the yashti. The yashti was surrounded by a chhatri or umbrella. There was also the presence of railing around the mound. Its purpose was to separate the sacred space from the secular world.