The lost city of Ubar is an ancient city on the Arabian Peninsula in southern Oman. Remains of the city were discovered in 1992 by archaeologists using remote sensing equipment. Ubar is believed to have been populated from about 2800 B.C. to about 300 A.D. and to have been at one time an important trading outpost, which gained importance with the rise of frankincense, the fragrant resin of a tree native to southern Arabia.
In this image, magenta represents regions of large sand dunes, green represents rough limestone rocks, and white represents a stream bed that remained dry except during the rainy season. The fortress of the lost city of Ubar is on the south western bank of this Dry stream bed.
The decline of Ubar was both sudden and gradual, a result of human activities and the mighty nature that brought about a change. The waters that watered countless caravans and had been drawn upon to irrigate a sizable oasis, had receded. The limestone shelf on which the fortress rested became less and less stable. Earthquakes in the surrounding areas cracked and split the limestone underlying the main stream, thus gradually bringing an end to the community that had once flourished in the oasis.
The author is thankful to Compton Tucker (NASA GSFC), Douglas Comer (Cultural Site Research and Management), and Devin White (Oak Ridge National Laboratory) for this article.