        
The Qasr al-Farid ('Lonely Castle' in Arabic) is located in the archaeological site of Madain Salih, to the northeast of Saudi Arabia's Hijaz mountains. The standalone tomb was constructed around the 1st century AD and is one of the most famous tombs in Madain Salih. It sits completely isolated from other tombs in the area; most tombs in Madain Salih were found in groups, which explains why this one is considered 'lonely.'