The Jameh complex is a veritable museum of Islamic architecture while still functioning as a busy place of worship. Showcasing the best that nine centuries of artistic and religious endeavour has achieved, from the geometric elegance of the Seljuks to the more florid refinements of the Safavid era, a visit repays time spent examining the details – a finely carved column, delicate mosaics, perfect brickwork. Covering more than 20,000 sq metres, this is the biggest mosque in Iran.