The construction of the Agra fort was started around 1565 when the initial structures were built by Akbar. Shah Jahan replaced most of these with his marble creations. Some however survived, among them are - Delhi Gate., Amar Singh Gate, Akbari Mahal and the Jahangiri Mahal. The fort is crescent shaped, flattened on the east with a long, nearly straight wall facing the river. It is ringed by double castellated ramparts of red sandstone punctuated at regular intervals by bastions. Deep moat surrounds the outer wall. High inner wall imparts a feeling of invincible defensive construction. The route through the Amar Singh Gate is dog-legged. The layout of the fort was determined by the course of the river, which in those days flowed alongside.
Gateways - The fort had originally four gates, two of which were later walled up. Delhi gate in the west is fortified by massive octagonal towers and faces the bazaar and leads to the Jama Masjid in the city.
Diwan-i-Khaas - To the right of Sheesh Mahal is Diwan-I-Khaas, the hall of Private Audience. Presently entry is not allowed inside Diwan-I-Khaas but the fine proportions of the building can easily be appreciated.
Sheesh Mahal - Opposite to the Musamman Burj and just below the Diwan-I-Khaas hall is the Sheesh Mahal or the Glass Palace. It is believed to have been the harem dressing room and its walls are inlaid with tiny mirrors which are the best specimens of the glass-mosaic decoration in India.
The other important sections of the fort are - Jahangir Mahal, Jodha Bai's Palace, Anguri Bagh, Golden Pavilions, Khaas Mahal, Musamman Burj, Hammam-i-Shahi, Diwan-i-Aam etc.