Petra (from πέτρα "petra," rock in Greek; Arabic: البتراء, Al-Butrā) is an archaeological site in Jordan, lying in a basin among the mountains which form the eastern flank of Arabah (Wadi Araba), the large valley running from the Dead Sea to the Gulf of Aqaba. It is famous for having many stone structures carved into the rock. The long-hidden site was revealed to the Western world by the Swiss explorer Johann Ludwig Burckhardt in 1812. It was famously described as "a rose-red city half as old as time" in a Newdigate prize-winning sonnet by John William Burgon. Burgon had not actually visited Petra, which remained accessible only to Europeans accompanied by local guides with armed escorts until after World War I. The site was designated as a UNESCO World Heritage Site in 1985 when it was described as "one of the most precious cultural properties of man's cultural heritage."