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.
Accompanying the Diwan-i-Khas, or Hall of Selective Audience, the Hamam (bathroom set) consists of three apartments interconnected by corridors. The marble floors and dados are inlaid with beautiful floral patterns of multi-colored stones.
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.
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.
Naubat Khana Naubat Khana, or Naqqar Khana (meaning the Drum House), is situated at the entrance of the palace area. Here music was played five times a day at the appointed hours. It housed a gate known as 'Hathi Pol' (Elephant Gate), where visitors dismounted from their elephants.