The Prophet's Mosque is one of the largest mosques in the world and the second holiest site in Islam (after the Grand Mosque in Mecca), and it is the mosque that the Prophet Muhammad built in Medina after his emigration in 1 AH 622 AH next to his house after the construction of the Quba Mosque. The mosque went through several expansions throughout history, through the era of the Rightly Guided Caliphs, the Umayya Caliphate, and finally during the era of the Saudi state, where its largest expansion took place in 1994.