The Citadel of Herat, also known as the Citadel of Alexander, is located in the center of Herat in Afghanistan. It is supposed to have been built around 330 BC, when Alexander the Great arrived to what is now Afghanistan. It has been a central military stronghold for many empires over the last 2000 years.
It is fashioned in the shape of an older, rectangular compound to the east, about eighteen meters by forty-two meters, protected with thirteen towers, all made of fired bricks, called the Upper Citadel. The Lower Citadel has lower walls of baked bricks and has a polygonal shape about twenty-five by sixty meters, with nine circular towers. In the light of the dawning sun, the citadel looks like a gigantic castle of sand.
Close to destruction in the middle of the 20th century, it has been progressively restored by various organizations and businesses up to 2011.