Hayu Cave

Hayu Cave lies in a beautiful mountainous area northwest of Hayu village, in the Vasevar recreational valley, close to the Hashtgerd–Qazvin road. Three caves can be seen here, about 15 metres apart, and studies suggest they may date back to the Paleolithic era. Hayu Cave was formed in layers of limestone roughly 265 million years old, but the cave itself is very young in structure. Its entrance is about 60 centimetres across and very steep, which makes it difficult to enter, although this may also have helped protect the cave naturally.

The interior consists of one large gallery, which in places is more than 23 metres high. Inside the gallery there are limestone formations such as stalactites and stalagmites, but unfortunately some of them have been destroyed through ignorance. The absence of complete columns, formed when these two kinds of formation join, may indicate that the cave is young, and it also raises the possibility of deeper galleries in its unexplored sections. The process of cave formation, which takes place in limestone layers through the infiltration of highly soluble water, usually takes millions of years.

Geologically, Hayu Cave is a valuable example of the natural processes that create underground spaces. The area's limestone, with its natural joints and fissures, provides ideal conditions for water to seep in and create such structures. The cave's scientific importance, together with its unique natural features, has made it one of the region's most interesting geological phenomena, although a lack of adequate care has put some of its valuable features at risk.