Lucknow city is home to `Bara Imambara`, which is classified as the last phase of Nawabi Moghul architecture. The Great Imambara is part of the Asaf-ud-daula Imabara complex that contains a mosque, courtyards, gateways and a `bawali` or step-well used as a summer palace. The complex is one of the earlier attempts in Lucknow to imitate a Mughal complex and incorporates high-arcaded battlements even when security was not a concern. The construction of the halls and the use of vaults show a strong Islamic influence. The Great Imambara is on axis with the triple arch gateway and occupies the southern extreme of the main courtyard while the Asafi mosque takes up the western. The tombs of Asafuddaulah and his relatives are also situated nearby. The Imambara is a unique architectural form that is used for ceremonies performed by Shia Muslims to commemorate the death of Hussain, grandson of Prophet Muhammad, at Karbala in 680 A.D.

The structure shows the mixture of Rajput and Moghul architectures with Gothic influences. The Bara Imambara is a large complex, which houses a mosque, courtyards and gateways. The Bara Imambara is a great hall, which is quite huge that stretches in an area of 900 sq mt, and said to be largest hall in world without any external support of wood, iron, or stone beams. The great hall is approached through two magnificent triple-arched gateways. The ceiling of this column less hall is more than 15-meter high. The hall is one of the largest of its kind in the world. The central hall of the Imambara is almost 50 meters in length and 16-meter wide. The roof has been put together with interlocking bricks without using a beam or a girder. Hence, it is viewed as a unique achievement of architecture.

The building, consisting of three huge halls, has an amazing maze of corridors hidden in between its walls that are about 20 feet thick. This dense, dark maze called the `bhul bhulaiya`, which is a network of more than 1000 labyrinthine passages, some of which have dead-ends, some end at precipitous drops while others lead to entrance or exit points. A unique thing about the building is that the main gate, also called as Rumi Darwaja, is visible from all the windows and galleries of the main hall, and it leads into a courtyard that connects to the main courtyard through a triple-arch gateway. This was done to ensure a good protection against any enemy intrusion. Another intriguing structure at the Imambara is the five-storied baoli (step well), which belongs to the pre-Nawabi era. Called the Shahi-Hammam (royal bath), this baoli is connected with the river Gomti. Only the first two stories are above water, the rest being perennially under water.

History of the Bara Imambara
The Nawabi architecture started when the Nawabs of Avadh had disassociated themselves from Delhi but fell under British control. The nawabs then were able to lavishly patronize architecture. As a result, the Great Imambara was built to grandiose scale, but in some aspects suffered from superfluous use of ornamentation. Nawab Asaf-ud-Daula built the Imambara in 1784 and its designer was Kifayat-ullah who is said to be a relative of the architect of the Taj Mahal. It was built as part of a famine relief program following the famine of 1784 and one of Asad-ud-Daulah`s objectives in embarking on this grandiose project was to provide employment for people in the region.

The famine continued for over a decade and the construction of the building continued for this time. It is said that ordinary people used to work in the day building up the edifice, while noblemen and other elite were called at night to break down all the structure raised, as they were incapable of doing anything else, according to a chronicle of the period. The construction continued for months and in return, the labors received money and food for their family. This see-saw efforts continued till the famine period was over. The main entrance gate, Rumi Darwaja, a huge 60-feet-high door was also built by Asaf-ud-Daula. It is also called the `Turkish Darwaza,` it is the entrance to the Bara Imambara.

Sites & Architecture
The Bara Imambara is a rectangular brick and mortar structure and in plan is divided into nine chambers. The central chamber is the largest and measures 164 feet by 52 feet (50 by 16 meters) and is over 49 feet (15 meters) high. The eight chambers surrounding the central bay are considerably smaller in both area and height and are more for circulatory purpose. The long central chamber has a concrete vault while the remaining bays are treated in a variety of roofing techniques. The arched roof of the central vault is built without beams, making it one of the largest concrete shells in the world. The central chamber contains the grave of Nawab Asaf-ud-daula and is the only Imambara that has six entrances into the central bay as opposed to the conventional five.

The exterior façade of the Imambara is problematic due to its monumental scale. The central bay and two flanking bays rise above the surrounding bays resulting in a stepped façade. The first level has arched openings and blind niches with octagonal towers marking the internal division of the bays on the exterior façade. The second level tries to break the scale of the facade by having a series of undersized arched openings, arches with latticework at the parapet, guldastas (ornamental minarets) and chattris (small kiosks). The disproportionate scale between the two levels renders the ornamentation of the façade as weak, and combined with the stepping back of the levels serves only to emphasize the ostentatious scale of the building. The numerous openings, however, have made it possible to create a unique feature in the form of a labyrinth. The imambara is popular amongst its visitors for the `Bhool Bhooliya` or labyrinth that is formed by the many balconies and passages that branch off from 489 identical doorways.