article_snippet.sent: Petra was the capital of the Nabataean kingdom and features a 250-foot-high  sandstone slot canyon known as the Siq.
article_snippet.sent: While Petra was the capital of the Nabatean kingdom, Mada'in Saleh was Mada'in Saleh second city, explaining why the unusual carved rock architecture is so similar.
article_snippet.sent: Petra Jordan was the capital of the Nabatean Kingdom.
article_snippet.sent: Petra is sometimes known as the Rose City due to the color of the smooth stone .