Sitting on top of a mountain in the northwest corner of Saudi Arabia is a mud and stone structure known as Za’abal Castle (or Zaabal Fort, Zaabal Palace). But it’s more than just a fortress, it sit on top of a well system that has run throughout the city of Sakakah for centuries.
The current structure—consisting of a wall surrounded with four watchtowers and a water reservoir—is believed to have been built 200 years ago. However, archeological evidence shows several structures have existed on this site since the first century AD. It’s prominence at the highest point in the area gives it a commanding view of the city, but it serves more than one purpose.
The courtyard of the fort is also designed to be a catch basin for water which is then fed into a well system that runs underneath the city. The wells are big enough for people to walk through, though they are closed to the public for safety reasons.