It dates back to 330 BC, when Alexander the Great and his army arrived to Afghanistan after the Battle of Gaugamela.
From decades of wars and neglect, the citadel began to crumble but in recent years several international organizations decided to completely rebuild it.
The National Museum of Herat is also housed inside the citadel, while the Afghan Ministry of Information and Culture is the caretaker of the whole premises.
The latest restoration involved hundreds of Afghan craftsmen and funds from the Aga Khan Trust for Culture and about $2.4 million from the U.S. and German governments.
Ambassador Ryan Crocker stated that: "Until 35 years ago, tourists from around the world came here to experience heritage, history and incomparable national landscapes... We look forward to the day when Afghans and visitors from around the world will once again come here to learn about Afghanistan's rich history and enjoy the great hospitality and beauty that this land and its people have to offer."