The city of Petra in Jordan was lost for centuries until being rediscovered by Swiss explorers in the 1800s. They had to travel narrow paths through impressive mountains of stone to reach the city. Upon arriving, they discovered structures like the Palace of Petra, also known as "The Treasure", which stands 42 meters tall. Petra was constructed in the 6th century BC by the Nabatéens during the Persian Empire and was used as a trading center for spices. The Nabatéens built sophisticated water systems including tunnels and tanks. One of their structures was a 4000 seat theater built in Greek-Roman style.