It is the country's largest mosque, built in 1656, where thousands of Muslims offer prayers. It lies opposite the Red Fort and is surrounded by a large number of shops, which deal in a variety of goods. The great mosque of Old Delhi is both the largest in India and the final architectural extravagance of Shah Jahan with a courtyard capable of holding 25,000 devotees.

This monument was built between 1644 and 1658 by five thousand artisans. Having three gateways, four angle towers and two minarets standing 40m high, it is constructed of alternating vertical strips of red sandstone and white marble. Originally called the Masjid-i-Jahanuma, or mosque commanding view of the world, this magnificent structure stands on the Bho Jhala, one of the two hills of the old Moghul capital city of Shahjahanabad. The main eastern entrance, probably used by the emperors, remains closed on most days of the week. The main prayer hall on the west side, houses a niche in a wall that shelters the prayer leader. Worshippers use this hall on most days but on Fridays and other holy days, the courtyard is full of devotees offering namaaz.