Imam Mosque (Masjid-e Jam 'e Abbasi), also called Masjid-e Shah (Royal Mosque) before the victory of Islamic Revolution, is one of the finest and the most stunning buildings in the world. The Mosque, begun in 1612 during the reign of Shah Abbas I and, despite the Shah's impatience, under construction until 1638 represents the culmination of a thousand years of mosque building and a magnificent example of architecture, stone carving, and tile work in Iran, with a majesty and splendor that places it among the world's greatest buildings.
The outer recessed portal faces north, as required by the placement of the Maidan, but since the axis of the mosque itself and that of the mehrab must be in the direction of Mecca (hence northeast to southwest), an awkward adjustment was necessary to avoid a serest of dislocation.
The portal, almost a building in itself and understood as an aspect of the Maidan rather than of the mosque, forms a welcoming embrace, inviting and guiding the throngs outside into the refuge, security and the renewal the mosque provides. In fact, it is the most thrilling example of human artifice that could be imagined. Its height amounts to 30 m, the flanking minarets are 42 m tall- with the sanctuary minarets higher still, 48 m. The two panels which flank the actual entrance within the recess carry the design of a prayer rug, a reminder of the mosque's essential purpose.
A mosaic tile inscription by Ali Reza Abbasi can be seen on the main portal of the mosque, which is dated 1616 AD (completion date of the portal). Below this, there is still another inscription that gives the name of the builder as Ali Akbar Esfahani, and that of the construction supervisor as Muhib Ali Beigallah. Several other inscriptions can also be seen on the portal and in the narthex of the mosque.
However, Shah Abbas needed a showplace, just as he needed the Sheikh Lutfollah Mosque for private meditation, and he built this whole gigantic structure, with two seminaries (ma4rasehs) in the few years from 1612 until his death in 1629, the year of the great copula's completion.
Through the outer portal one enters a noble vestibule, which is a usual feature. Octagonal, it has no particular direction; it can therefore serve as a pivot on which the axis of the building is turned, the gateway to another world of splendor and concentrated power.
Of the classical-Jour ivans the west ivan has a wide porch surmounted by a goldasieh (minaret). The south ivan (also the largest) opens to reveal a great prayer hall surmounted by a double cupola 38 m high on the inside and 52 m on the outside (leaving a 12-meter empty space which serves as an extraordinary "echo chamber", since a speaker in the mehrab can be distinctly heard in all other parts of the mosque), its surface decoration being of the most sumptuous richness, a floral design in gold, yellow and white spiraling on a deep blue ground. In the center of the great prayer hall look out for a few black paying stones underneath the dome, which when stamped upon create seven clear echoes. Try it for yourself; everyone else does.

The fact that sound is equally carried to all parts of the dome chamber and cloisters on each side as well as to the courtyard and the lateral porches indicates that four centuries ago, Iranian architects were able to produce buildings provided with acoustics not inferior to those of any modern building.
Great jasper and marble bowls like fonts each made of a solid stone block, can be seen near the portal gate, under the western and eastern domes, and in the cloisters on both sides of the great southern prayer hall. These are unique in terms of delicacy and care with which they were made. They used to be filled, on various with water 91 sherbet to quench the thirst of worshipping throngs in summer.
To the east and west of the mosque there are two madrasehs (theological colleges). Two long seminaries at the back are suitably studious in their architectural tranquillity. The dome, elegant and sensitive in contour, slightly bulbous, set on a high drum, is simple, of remarkably clean and expressive outline uncluttered by any supplementary constructions.
In the school building to the southwest of the courtyard there ,is a piece of stone which acts as a sundial attributed to Sheikh Bahai, the famous scientist and mathematician of the period of Shah Abbas. It indicates noon in Esfahan throughout the year.
According to A U Pope, both the ground plan and the structure of the building reflect the doctrinal simplicity of Islam. Circulation and communication are everywhere facilitated, nowhere impeded. The common floor level is at no place broken by steps, railings or screens. The walls merge into their garden-Iike floriation or open onto real and natural gardens. Because of the concentration of the bearing load on octagonal stone columns, wide vistas open up and voids are at maximum. The ornamentation is wholly traditional, repeating the Iranian motif of appeal for fertility and abundance. Almost the entire surface of the building is covered with enamel tile. A vast display of floral wealth, abstract and imaginative, emphasizes the Persian poetic passion for flowers, as well as the appeal for a continuance of an abundant life. The best time to photograph is about II am when the sun is overhead