Which is the 1st Mosque in the World?

The first mosque in the world is generally considered to be the Mosque of the Prophet, also known as the Mosque of Medina or the Prophet's Mosque. 

It was built by the Prophet Muhammad and his followers in Medina, present-day Saudi Arabia, in the 7th century.

According to Islamic tradition, the Mosque of the Prophet was the first place of worship for Muslims and played a central role in the development of Islam. 

It was also where the Prophet Muhammad lived and preached and where many of the critical events in the early history of Islam took place. 

The mosque has undergone several renovations and expansions over the centuries, but it remains an important place of pilgrimage for Muslims from around the world. It is considered one of the holiest sites in Islam and is the second most sacred site after the Mosque of Mecca.