The Ali Sadr Cave originally called Ali Saadr or Ali Saard (meaning cold) is the world’s largest water cave which attracts thousands of visitors every year. It is located in Ali Sadr Kabudarahang County about 100 kilometers north of Hamadan, western Iran (more accurately at 48°18’E 35°18’N). Because of the cave’s proximity to large cities such as Hamadan, it is a highly recommended destination for tourists from all corners of the world.
According to geologists, the stones of this mountain belong to the second geologic period, i.e. Jurassic Era (136-190 million years ago). Evidence from the cave indicates that Ali-Sadr Cave has been used as shelter by primitive men. Extraordinary natural patterns such as Statue of Liberty and name of Allah have been carved on the limestone walls of the cave.
Excavations and archeological studies of the cave have led to the discovery of ancient artworks, jugs and pitchers dating back to 12,000 years ago. Animals, hunting scenes and bows and arrows are depicted on the walls and passages of the exit section. These images suggest primitive man used the cave as their abode. The cave was known during the reign of Darius I (521-485 BC) which can be verified by an old inscription at the entrance of the tunnel. However, the knowledge of the existence of the 70-million-year-old cave was lost, and it was only rediscovered in 1963 by Iranian mountaineers.
The cave walls can extend up to 40 meters high, and it contains several large, deep lakes. The cave has a river flowing through it and most travel through the cave system is done by boat. More than 11 kilometers of the cave’s water canals have been discovered so far. Some routes are 10 to 11 kilometers long and all lead to “The Island”, a centrally located large atrium.
Unlike many other aquatic caves, the body of water in Ali Sadr is not a flowing river, but rather an extensive, web-like lake seemingly fed by spring waters from nearby Sarab Cave. Visitors to Ali Sadr are conducted to an underground wharf where they board boats that take them gliding silently through this chain of flooded chambers.
The combination of rainwater and CO2 formed mild carbonic acid which seeped into the calcareous fields and through chemical reactions, unstable sodium bicarbonate was formed. This soluble chemical composition created abyss the thick calcareous layers.
Colorful, glittering geological structures cover the tunnel walls above and below the surface of the water, which is clear enough to provide visibility to a depth of five meters. Tight, winding passageways branch off endlessly from one another, or open up into massive rooms like the Wedding Room (also called the 1000 Stalactites Room), the Island (which sits at the center of the complex), and the 600-meter-long Freedom Hall (the largest chamber in the network).
Prehistoric paintings, pitchers, and jugs found onsite indicates that the cave were inhabited by early humans starting 12,000 years ago. An additional entrance to Ali Sadr was constructed during the reign of Darius I (521-485 BCE), but at some point after that the cave was apparently forgotten, being rediscovered only in 1963. Since then it has been explored by mountaineers and geologists from both Iran and abroad. Its known extent at this point stretches over 11 kilometers, with its longest passage mapped thus far running almost the same distance.
Its colorless water is odorless and has natural taste. There are no living creatures in the cave’s water and its temperature is 12 degrees centigrade. The water is so transparent that one can see to the depth of 10 meters with the naked eyes and ordinary light. The results of physical and chemical experiments show that the chemical composition of water is approximately the same as in different parts of the cave and is considered as light calcic bicarbonate with nearly neutral pH (acidity). The water is not drinkable since it contains different calcareous salts.