It is Octagonal shapedRed Fort in Delhi, c. 1905.
The fort is located beside the river Yamuna. A massive wall was built around the fort to protect it from the external attacks. The wall is build of red sand stone.
That is why the fort is called red fort. The fort have two entrances- Lahore gate and Delhi gate. The shape of this fort is octagon and it covers 256 acres of land.