Imām Reza shrine in Mashhad, Iran is a complex which contains the mausoleum of Imam Reza, the eighth Imām of Twelver Shi'ites. It is the largest mosque in the world by dimension and the second largest in capacity.
Also contained within the complex include: the Goharshad Mosque, a museum, a library, four seminaries, a cemetery, the Razavi University of Islamic Sciences, a dining hall for pilgrims, vast prayer halls, and other buildings.This complex is the center of tourism in Iran.
Although the earliest dated structure bears an inscription from the early fifteenth century, historical references indicate buildings on the site prior to the Seljuk period, and a dome by the early thirteenth century.
The tomb chamber is located underneath a golden dome, with elements dating back to the twelfth century. The chamber is decorated with a tilework dado dating from 612/1215, above which the wall surfaces and a muqarnas dome were executed in mirror work in the nineteenth century.
Shah Tahmasp gold-plated the tomb dome, which was previously decorated with tile. The gold of the dome was lost to Ozbeg raiders and subsequently replaced by Shah Abbas I .
Various other chambers surround the tomb, including the Dar al-Siyada and Dar al-Huffaz, both commissioned by Gawhar Shad. These two chambers provide transition between the tomb chamber and her congregational mosque, situated on the southwest side of the complex.
The assemblage of courts and buildings encircling the inner chambers includes the Mosque Of Gawhar Shad, the Madrasa Do Dar, the Sahn-e Engelab or Sahn-e Atiq (the old courtyard), and the Sahn-e Azade or Sahn-e Jadid (the new courtyard).
These are described in individual entries.
Each year, the Shrine of Imam Reza, Iran's most sacred religious site, draws millions of Shiite Muslim pilgrims to Mashhad.
References:
www.en.wikipedia.org
www.archnet.org/library/sites/one