Overview
The Great Dam of Marib stands in the Wadi Adhanah (Dhana) in the highlands of eastern Yemen, roughly 170 kilometres east of Sanaʿa, just upstream of the ancient Sabaean capital. Construction of successive earth-and-rubble dams with cut-stone spillways and sluices began by the early first millennium BCE; epigraphic and archaeological evidence places major works between the eighth and sixth centuries BCE, with repeated repairs and enlargements under Sabaean and later rulers.
Unlike many ancient retention dams, Marib was designed primarily for controlled diversion: monsoon floods were slowed, diverted through twin northern and southern canals, and distributed across a vast oasis network capable of supporting tens of thousands of people and the frankincense-and-myrrh agricultural economy of South Arabia. Classical authors and local inscriptions celebrate Marib as a green oasis amid the desert; Quranic tradition later remembered the "flood of the dam" (sayl al-ʿArim) as a civilisational turning point.

Jemen1988-022 hg | H. Grobe (CC BY-SA 3.0)
"There was for Saba a sign in their dwelling-place: two gardens, on the right and on the left. Eat of the provision of your Lord and be grateful to Him. A good land and a forgiving Lord. But they turned away, so We sent upon them the flood of the dam."
— Qurʾan 34:15–16 (Sūrat Sabaʾ), on the flood of the dam at Marib
The final catastrophic failure is conventionally dated to the mid–late sixth century CE (after centuries of repair episodes), after which the oasis contracted and the political centre of gravity in Yemen shifted toward Himyarite highland capitals. Modern hydraulic works nearby (opened 1986) sit upstream of the ancient ruins; the archaeological remains of sluices, abutments, and canal heads remain among the most important engineering monuments of the ancient Arabian peninsula.

083 stari jez | Ljuba brank at Slovenian Wikipedia (Public domain)
Marib and its surrounding Sabaean landscape form part of UNESCO's recognition of the Landmarks of the Ancient Kingdom of Saba (inscribed 2023).
