The ancient Nabataean capital of Petra, in Jordan—where a once-nomadic tribe established a boomtown of trade—attracts over a million visitors a year. A few hundred miles south is Hegra. This cluster of 100 or so surviving Nabataean tombs has never officially opened to the public, until now. Although Petra’s tombs outnumber Hegra’s six to one, the latter’s are far better preserved, and offer further insight into a 2,000-year-old civilization still shrouded in mystery. Etched into the tomb façades are intimidating inscriptions written in a precursor to modern Arabic. Classical Greek and Roman architecture combine with Nabataean symbols, waiting to transport souls to heaven. Hegra’s largest tomb, measuring about 72 feet tall, was left unfinished, making for the striking sight of an intricate entrance carved into the side of a giant, solitary desert boulder. —J.V.