Takht-e Soleyman is an outstanding ensemble of royal architecture, joining the principal architectural elements created by the Sassanians in a harmonious composition inspired by their natural context. The composition and the architectural elements created by the Sassanians there have exerted a strong influence not only in the development of religious architecture in the Islamic period, but also in other cultures. The ensemble represents an outstanding example of a Zoroastrian sanctuary, integrated with Sassanian palatial architecture within a composition, which can be seen as a prototype..
The site consists of an oval platform about 350 m by 550 m rising 60 m above the surrounding valley. It has a small calcareous artesian well that has formed a lake some 120 m deep. From here, small streams bring water to surrounding lands. The Sassanians occupied the site starting in the 5th century, building there the royal sanctuary on the platform. The sanctuary was enclosed by a stone wall 13m high, with 38 towers and two entrances (north and south). This wall apparently had mainly symbolic significance as no gate has been discovered. The main buildings are on the north side of the lake, forming an almost square compound (sides c . 180 m) with the Zoroastrian Fire Temple (Azargoshnasb) in the centre. This temple, built from fired bricks, is square in plan. To the east of the Temple there is another square hall reserved for the 'everlasting fire'. Further to the east there is the Anahita temple, also square in plan. The royal residences are situated to the west of the temples.
The lake is an integral part of the composition and was surrounded by a rectangular 'fence'. In the north-west corner of this once fenced area, there is the so-called Western iwan , 'Khosrow gallery', built as a massive brick vault, characteristic of Sassanian architecture. The surfaces were rendered in lime plaster with decorative features in muqarnas (stalactite ceiling decoration) and stucco. The site was destroyed at the end of the Sassanian period, and left to decay. It was revived in the 13th century under the Mongol occupation, and some parts were rebuilt, such as the Zoroastrian fire temple and the Western iwan . New constructions were built around the lake, including two octagonal towers behind the iwan decorated in glazed tiles and ceramics. A new entrance was opened through the main walls, in the southern axis of the complex. It is noted that the surrounding lands in the valley (included in the buffer zone) contain the remains of the Sassanian town, which has not been excavated. A brick kiln dating from the Mongol period has been found 600 m south of Takht-e Soleyman. The mountain to the east was used by the Sassanians as a quarry for building stone.