Joatha Mosque

Joatha Mosque is in the Jawāthā, about 12 km northeast of Hofuf, Al-Ahsa, Saudi Arabia. It was the earliest known mosque built in eastern Arabia, and most of the original structure is in ruins, nevertheless, the site is still used for prayer. The date of the mosque's original construction as either 628 CE or 635-636 CE from various sources. It was built by Bani Abd al-Qays tribe, who lived there before and during the early Islamic period. It is believed to be the first mosque built in Eastern Province and where the second Friday congregation prayer in Islam was offered, the first being held in the Prophet's Mosque in Medina. 

According to legend, when the Hajr Al-Aswad (Black Stone) was stolen from Mecca by the Qarmatians, it was kept in this mosque for nearly 22 years. Most of the mosque's original structure has been lost and it remains in danger of collapse. Only a small number of its arches from the historic mosque today, probably dating from around the 9th century AD. The remains include two pointed keel arches from one arcade of the mosque and a part of the qibla wall consisting of three keel-arch niches. The central niche of the qibla wall is larger than the other two and acts as the mihrab, which projects from the outer side of the wall. In modern times, sometime before 1983, these remains were cleared of sand and enclosed by a structure of concrete walls and covered with a protective roof, which remains today.