Shah Jahan was a great builder and was trained as a Prince in architecture at Ahmedabad when he was the Governor of Gujarat, where he constructed the elegant Shahi Bagh palace. He had great resources and a superior sense of building art. Marble was already used by Jahangir. The Pleasure Palace (now Tomb) of Itimadud-Daula at Agra is one of the finest buildings of its kind with profuse pietra dura work on the outer surfaces and lime stucco work with paintings in the interior surfaces.
Shah Jahan was greatly inspired by such masterpieces and built his palaces at Agra and Lahore Forts, after demolishing red sandstone structures of Akbar and Jahangir in 1637.
Suiting his taste, Shah Jahan constructed the Khas Mahal which was called Aramgah-i-Mualla (The exalted place of rest) or Aramgah-i-Muqaddas (The holy resting apartment) as is mentioned by Abdul Hamid Lahauri in his Badshah Nama. The building comprises open Terraces and a hall, flanked by a pavilion on either side serving as partitions. The structure is erected on a sufficiently elevated platform paved with marble. It is the royal palace of the Emperor, splendidly set the Harem complex which includes curtain walls (Sar-i-parda), elegant tanks, fountains and a waterfall (chadar) surrounded by living apartments with courts and verandahs. The palace is laid out in three receding levels, namely the main palace overlooking the river with spacious open terraces and garden in front of it standing majestically in a delightful setting, reflecting the fine aesthetic sense of Shah Jahan.
The main palace consists of a Central Hall with alcoves and rooms on sides and a large dalan on its front facing an open platform with tank and fountains overlooking the garden now called Anguri Bagh. The complex is built in chaste marble, which was originally fabulously painted and gilded in gold.
Originally the niches above the dados were decorated with Imperial portraits. The dalan is composed of cusped arches, supported on square piers. The roof of the portico is surmounted on engrailed arches. An elegant rectangular tank with scalloped border is in the centre of the platform facing the so-called Anguri Bagh. The water rippled through a shallow canal to the waterfall behind with chini-khana (series of canal niches) is provided with such water devices. A rainbow is created when the fountains play with coloured water. These water devices created an enchanting cool atmosphere during hot weather.