Though little is visible but its foundations, to look on the remains of Erum is to look on a legend. The “City of 1,000 Pillars,” which flourished between 3,000 BC and the 1st century AD, was discovered in the 1980s using satellite technology to track its whereabouts in the Rub’ al-Khali Desert. Until then, it was thought to exist only in folk tales and ancient records, including the Qur’an.
The Rub’ al Khali is the sand desert encompassing most of the southern third of the Arabian Peninsula. The desert covers some 650,000 km² including parts of Saudi Arabia, Oman, the United Arab Emirates, and Yemen. It is part of the larger Arabian Desert. Wikipedia