The Azadi Tower is the iconic gateway monument of Tehran, an elegant white marble arch completed in 1971 to mark the 2,500th anniversary of the Persian Empire. Blending modern and traditional Iranian architecture, it stands at the centre of a large square that has been the stage for many historic events. A museum lies beneath it, and the structure is beautifully lit at night. Instantly recognisable, it is the enduring symbol of the capital and a must-see landmark for visitors.