The Al-‘Abbās Mosque or Masjid al-‘Abbās is the mausoleum of ‘Abbās ibn ‘Alī, located across from the Imām Husayn Mosque in Karbalā, Iraq. ‘Abbās was the brother of Hasan and Husayn, and was the flag-bearer for Husayn in the Battle of Karbalā. The distance between the shrines of ‘Abbās and Husayn, are the same as the distance between the hills of Al-Safa and Al-Marwah.
Environmental effects over the years have caused the Euphrates river to change direction. Nearly 1400 years after the Battle of Karbalā, the river flows across the grave of ‘Abbās and encircles it. It is said that the Euphrates has come to ‘Abbās now.
Emperors and kings of various dynasties have offered valuable gifts and gems to the shrine of ‘Abbās. In 1622 Abbas Shah Safavi ordered the decoration of the grave's dome. He built a window around the grave and organized the precinct.