Carved directly into the rugged volcanic rocks of the Wadi Tawila valley, the Al-Saharij Cisterns are one of antiquity's most impressive engineering achievements. Located in the city of Aden, this complex of cisterns served as the primary life source for the local population for centuries, collecting and storing rare rainwater in the heart of the arid land known as Yemen.

This historical landmark is striking in its scale: there were once more than 50 reservoirs connected in a complex system. Today, 13 of them are open to the public, including the famous Coghlan Tank and the circular Playfair Tank. The total capacity of the surviving structures is an impressive 19 million gallons, demonstrating the profound knowledge of hydraulics and construction held by ancient master builders.
The walls of the reservoirs are coated with a special compound that has kept them impermeable for centuries. For tourists, this site is valuable not only as a historical monument but also as a magnificent observation deck: the steps of the ancient structures offer panoramic views of the surrounding hills and city quarters, providing an ideal backdrop for reflecting on the power of human genius.