The building of the blue dome of Marāgheh which is known as the Hulāku dome, is a decagon-each side measuring over six meters-tall 10 meters with red bricks, turquoise majolica and white stones, and in the past was equipped with a conical dome that with the passage of time has been lost.
This consisted of two parts, the crypt and the main room. The sides of this tower have arches, work on the margins and are notched and next to it have been made of columns-like bases.
The decorations of the external body of the dome are a muqarnas in a straight line and in geometric shapes and three series of muqarnas simple and pieces of very precious majolica have been placed between the rows of bricks laid.
Inside the crypt there is an inscription worked in stucco and a stone in a single block that belongs to the original building and its walls are decorated with words like "Allah", "Al-Hamd", with different shapes in calligraphy cufic and turquoise paintings.
On this dome which is located next to a circular tower, since ancient times many stories have been told.