Prophet Muhammad's Mosque, also known as Al-Masjid an-Nabawi, is located in Medina, Saudi Arabia. It is one of the holiest sites in Islam and was originally built by Prophet Muhammad himself in 622 CE. The mosque has undergone several expansions over the centuries and can now accommodate millions of worshippers during the annual Hajj pilgrimage. The mosque is famous for its beautiful architecture, including the iconic green dome that marks the burial place of Prophet Muhammad. It serves as a central place of worship and community for Muslims, offering daily prayers and special events throughout the year.