Shah Jahan shifted his capital from Agra to Shahjahanabad and laid the foundation of the Red Fort or Lal Quila on the April 16, 1639. It took nine years to build this strong city and I have ended April 16, 1648. It is said that about one crore rupees, an astronomical sum in those days, was used for its construction. Half of this sum was spent to build the exotic palaces within the fort. Built of red sandstone, is octagonal, with two longer sides on the east and west.
The perimeter of the walls is about 2.41 kilometers strong. Red Fort stands at a height of 33.5 m on the side of the city and 18 m along the River. Surrounded by a wide moat of the fortress, which was originally connected with the river and was always full of water. The two main entrances, known as Lahori Gate and Delhi Gate (so named because they face Lahore and Delhi, respectively) are three stories high and are flanked by semi-octagonal towers. They are located in central west and south sides, respectively.
The main entrance of Lal Quila is through the Lahori Gate. Beyond the door there is a covered walkway, flanked by arcaded apartments leading to the palace, known as Chhatta Chowk. These apartments are used as shops. Besides these, there are three doors in other places, which are locked now. The master builders of the Red Fort were Hamid Ahmad. Visitors are allowed only in a part of Red Fort, as the army occupies the rest of it. Some of the main buildings inside the fort are:
Diwan-i-Am or Hall of Public Audience in the Red Fort in Delhi. Originally it had a patio in the front and was richly decorated with gilded stucco. Heavy curtains hung in the main hall, which were three bays in depth.
Accompanying the Diwan-i-Khas, or Hall of selective hearing, the Hamam (bath set) consists of three apartments connected by corridors. The marble floors and are given floral designs inlaid with beautiful colored stones.
The mosque Aurungzeb staff, Moti Masjid or Pearl Mosque, located west of Hamam. Situated on a level above the courtyard, the prayer hall of the mosque with inlaid black marble contours of 'Musalla' (small carpets for prayers) and is surmounted by three bulbous domes.
One of the six main palaces along the river front, Mumtaz Mahal was also known as' Chhoti Baithak. A beautiful water channel called "Nahr-i-Bihisht '(ie, the Stream of Paradise) flew through these palaces. However, this palace has been removed, probably because it was totally ruined.
Naubat Naubat Khana Khana, or Naqqar Khana (which means House of the drum), is located at the entrance of the palace area. Here the music was played five times a day at fixed hours. It is a door called "Hathi Pol (Elephant Gate), where visitors dismounted from their elephants.