The Great Mosque of Samarra was built in the ninth century when Samarra served as the Abbasid capital. For a time it was the largest mosque in the world, its outer walls enclosing an enormous prayer space.
Its most famous feature is the Malwiya, a spiral minaret rising in a widening helix that can be climbed by an external ramp — a form found almost nowhere else in Islamic architecture.
The mosque anchors the archaeological city of Samarra, one of the largest surviving planned capitals of the early Islamic world.