Shah Jahan shifted his capital from Agra to Shahjahanabad and laid the foundation of Red Fort, or the Lal Quila, on 16th April 1639. It took nine years to build this mighty citadel and it got completed on 16th April 1648. It is said that about one crore rupees, an astronomical sum in those days, was spent on its construction. Half of this sum was spent to build the exotic palaces within the fort. Built of red sandstone, it is octagonal in shape, with two longer sides on the east and west. The perimeter of its strong ramparts is about 2.41 km. Red Fort rises to a height of 33.5 m on the town side and 18 m along the river. A wide moat surrounds the fort, which was originally connected with the river and was always filled with water. The two main gateways, known as Lahori Gate and Delhi Gate (named so, as they face Lahore and Delhi respectively),are three storeys high and are flanked by semi-octagonal towers. They are situated on the centre of the western and southern sides respectively.
The main entrance to the Lal Quila is through the Lahori Gate. Beyond the gate, there is a roofed passage, flanked by arcaded apartments leading to the palaces, known as Chhatta Chowk. These apartments are now used as shops. Besides these, there are three more gates on other sides, which are kept closed now. The master builders of the Red Fort were Hamid and Ahmad. Visitors are allowed only in a part of Red Fort, as the army occupies the rest of it. Some of the main buildings within the fort are:
Diwan-i-Am or Hall of Public Audience is situated in the Red Fort of Delhi. It originally had a courtyard on its front and was richly ornamented with gilded stuccowork. Heavy curtains graced the main hall, which were three bays in depth. The facade of nine openings of the arches rendered it a regal and imperial look that impresses the visitors even today. One can easily imagine the splendor of the court, covered with carpets and adorned with heavy chandeliers. It would have easily dazzled the people who visited the emperor to pay their humble homage. The emperor must have presented a really grand sight, seated on his throne in the marble canopy or baldachin, which was covered most appropriately by the beautiful 'Bengal' roof.
The personal mosque of Aurungzeb, Moti Masjid or Pearl Mosque lies to the west of Hamam. Situated on a higher level than courtyards, the prayer-hall of the mosque has inlaid black-marble outlines of 'musallas' (small carpets for prayers) and is surmounted by three bulbous domes. It is said that these domes were originally copper plated and even the eastern door is plated with copper leaves. The ladies of the seraglio also used the mosque to offer their prayers to God.
One of the original six main-palaces situated along the river front, Mumtaz Mahal was also known as 'Chhoti Baithak'. A beautiful water channel called 'Nahr-i-Bihisht' (meaning Stream of Paradise) flew through these palaces. However, this palace has been removed, probably because it was totally in ruins. The emperor used it to listen to the complaints of the general public and receive their petitions here only. It has a marble dais, inlaid with precious stones, below the throne and beautiful panels, inlaid with multicolored and semi-precious stones, adorn its walls. These panels were said to be designed by the Florentine jeweler, Austin de Bordeaux. The central panel depicts the Greek god Orpheus with his lute. These panels were shifted to the Victoria and Albert Museum in London by the British but were restored later in 1903, at the request of Lord Curzon.