Clad in black abayas and sun-shielding straw hats called nakhls, women work the fields in central Yemen’s Wadi Hadramawt, an oasis on the southern periphery of Arabia’s Rub al Khali, or Empty Quarter. Occupying a fifth of the Arabian Peninsula, the Rub al Khali is the world’s largest sand sea.

(Text adapted from and photo shot on assignment for, but not published in, "Empty Quarter: Exploring Arabia’s Legendary Sea of Sand, " February 2005, National Geographic magazine)