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The mind-blowing engineering of a 13th century clock controlled entirely by water

Want to see a fountain with 12 water-spewing lions tell you what time it is?

Jebulon (Public domain)

Alhambra palace in Granada, Spain is an architectural masterpiece and engineering wonder.

Modern life is filled with so many incredible innovations, it's enough to make your head spin. But as we marvel over the latest technologies, it can be easy to forget that humans have been engineering and creating remarkable things for millennia.

The pyramids in Egypt. The Colosseum and the Parthenon. Teotihuacan and Machu Picchu. We can point to many famous ancient wonders that demonstrate the advancement of civilizations around the world, but some slightly newer architectural wonders also provide a glimpse into humanity's ability to figure things out.

Alhambra palace, fortress, water system, Spain, ancient technologyThe Alhambra sits atop a plateau overlooking Granada, Spain.Ввласенко

The Alhambra is a palace and fortress in Granada, Spain, that was built between 1238 and 1358 and was home to sultans of the Nasrid dynasty. A celebrated example of Islamic architecture, the Alhambra is now a tourist site, but in its early centuries, it helped Granada remain unconquered by Christian crusaders for far longer than the rest of Spain. Its massive complex sits atop a plateau, making it hard for invaders to breach its fortress walls.

But the Alhambra's beauty and defensive strength are only part of its allure. Visitors who walk through the grounds will notice something that seems unlikely considering the palace's flat location high above the river—water features galore.

The Alhambra has pools, baths, fountains, and gardens—and featured even more of them in its prime. But how? Via an intricate system of medieval pipes and channels and hydraulic engineering that enabled not only pools and baths, but heated flooring, steam rooms, and perhaps even an incredible water-operated clock.

- YouTubewww.youtube.com

The Fuente de los Leones (Fountain of Lions) is a central feature of the palace. Just looking at it you wouldn't imagine it was a clock, but there is a serious hypothesis that it was and that it ran completely on water.

A circular fountain sits in its center surrounded by 12 lion statues facing outward. The clock hypothesis posits that the original fountain pool drained and filled on a 12-hour cycle, with 12 holes in the pool positioned in a graduating spiral, each one connected by a pipe to a lion's mouth. As a central pipe filled the fountain pool, the water reached each hole on an hourly basis, making water pour out from the corresponding lions' mouths. When water poured from the first lion, it was 1:00, when it poured from the first and second lion, it was 2:00, and so forth. Once the pool filled and reached 12:00, a syphoning mechanism triggered by the height of the water caused the pool to drain, and the cycle began all over again.

(To see how this clock and water system would have worked in action, see minute 4:56 in the Primal Space video above.)

fountain of lions, lion water clock, fuente de los leones, the alhambra, engineeringFountain of the Lions at the Alhambra, GranadaJebulon (Public Domain)

A restoration project in the early 2000s to mid 2010s brought the fountain back to life, but not as a clock. The fountain has been changed many times over the centuries, and no one knows for sure what the original design was.

The fountain is just one part of the whole elaborate Alhambra water network. Water from the fountain flowed out to four channels that led to spa-like bathing rooms, which featured a cold plunge, warm pools, and heated floors thanks to water flowing through copper stoves underground. They even had steam release pipes to create a steam room.

baths inside the Alcazaba, Alhambra, granada, spain, waterworks Remains of baths inside the Alhambra AlcazabaR Prazeres

But one of the other impressive engineering feats of the Alhambra water system was pushing water up a six-meter wall. Without modern water pressure technology, how did they do it? The Primal Space video above shows a kind of whirlpool pump in which a vortex adds air to the water, making it lighter and easier to push up the pipe vertically. However, the illustration in the video appears to be missing an outlet pipe at the bottom that a diagram from "The Mastery in Hydraulic Techniques for Water Supply at the Alhambra" published in The Journal of Islamic Studies shows, which makes the mechanics seem more plausible.

At the time, Alhambra had of the most sophisticated hydraulic networks in the world, bringing water from the river nearly a kilometer below the site and keeping it flowing through the property in gravity-defying ways. What an incredible feat of engineering and ingenuity.