Camp of Diocletian - Credit: Wikimedia Commons
The Camp of Diocletian was a Roman military complex, or castra, built in the ancient city of Palmyra in the Syrian Desert. The complex was built under the Roman Emperor Diocletian in the late third-century CE and served as the military headquarters for the Legio I Illyricorum.Pollard, 2000, p. 298. Read more on Wikipedia
Source: en.wikipedia.org