Historically, Edinburgh Castle relied on the Fore Well, a vital lifeline cut deep into the volcanic rock upon which the fortress sits. First appearing in records in 1314, this well was a primary source of water during the castle's many sieges, including the "Lang Siege" of 1573. However, the well often struggled to supply the entire garrison, especially during prolonged attacks when falling masonry could block it or the water level would drop. In such times, the water was occasionally reported as unfit for drinking. Rainwater harvesting from the surrounding rock and soil also supplemented the supply. By the 18th and 19th centuries, more modern piping and storage tanks were introduced to support the permanent military garrison, but the ancient Fore Well remains a prominent archaeological feature today, documented by modern 3D laser scanning.