Masjid al-Haram is the largest mosque in the world. Located in the city of Mecca, it surrounds the Kaaba, the place which Muslims turn towards while offering daily prayers and is considered the holiest place on Earth by Muslims. The mosque is also known as the Grand Mosque. The current structure covers an area of 400,800 square meters (99.0 acres) including the outdoor and indoor praying spaces and can accommodate up to 4 million worshipers during the Hajj period, one of the largest annual gatherings of people in the world.