The Shah Mosque (also known as Mosque of the 72 Martyrs) lies a short walk west of the Imam Reza Shrine complex. The original structure dates from the early 15th century and was rebuilt several times under the Safavids; the present building, much restored, retains a fine 15th-century mihrab and parts of the original tilework.
The mosque is functioning and welcomes respectful visitors outside prayer times. A useful stop on a walking route between the shrine and the bazaar.