Standing at the bottom of a dusty wadi, I crane my neck to take in the huge structure rising above me: row upon row of precisely cut stone, set seamlessly without mortar some 2,500 years ago, soaring 50 feet into the fading desert sky.
To call this ancient engineering marvel a mere dam feels almost derogatory. When the Great Dam of Marib was built in what is now Yemen, its earth-and-stone walls spanned an area nearly twice as wide as Hoover Dam. The still standing colossal sluices were part of a sophisticated system that controlled the flow of seasonal rains from Yemen’s highlands to its parched desert in the east, nurturing agricultural oases across almost 25,000 acres of wasteland. And in the middle of it all, a thriving economic hub: Marib, capital of Saba, the Arabian kingdom most famously associated with its legendary leader Bilqis, immortalized in the Bible and the Quran as the queen of Sheba.
At Marib’s peak, starting in the eighth century B.C., this dam was the source of prosperity for the Sabaean capital—and the reason it existed as a fertile, food-producing, water-abundant stopping point for thirsty camels and hungry traders.