Tehran Freedom Tower, IKONOS satellite image. North is at top. The Freedom Tower (Azadi Tower) is in the plaza and roundabout at centre left. Originally called the Shahyad Tower (Kings' Memorial), this 'Gateway to Iran' was constructed in 1971 to mark the 2500th anniversary of the Persian Empire. It was renamed in 1979 to mark the Iranian Revolution and the establishment of the Islamic Republic of Iran. Crowds on the west-east Azadi Road are marking the 31st anniversary of the Iranian Revolution. This image was obtained at 10:47am local time on 11 February 2010. IKONOS is operated by US company GeoEye.