The Caves of Hotton were formed millions of years ago. Far from the human eye, a warm sea used to cover parts of Belgium. Dying organisms such as plankton and corals lost their silicate shells which created sedimentary layers over a long period of time at the bottom of the ocean. Forces of the Earth transformed it into the limestone we see today in the region called the Calestienne.
A softer material ties the layers of sedimentation together. These joints crack when vertical pressures from the center of the Earth push the rock. With time, water starts flowing in between the cracks until it reaches far below the surface. The erosion is accentuated because limestone is saturated with calcium carbonate. Water and carbon dioxide act together by dissolving calcium carbonate from the rock. Water binds with carbon dioxide when passing through the atmosphere and organic soils. Caves are therefore slowly formed after a long period of time because water and carbon dioxide erode away bits in the limestone.
It is only in 1958 that the Caves of Hotton were first discovered. A blow in a mine above the caves disclosed its opening. It was soon closed after that because the owner worried that curious and passersby might interfere with the activity of the mine. It’s only later that a team of Belgian speleologists entered the caves through another breach found outside of the quarry. The team had to dig through a tall funnel filled with clay before they finally reached the caves. They discovered a massive room and a whole network of tunnels going on different levels.
Visitors have access to the Caves of Hotton since 1962. Pits, rooms and superb underground galleries connect to a depth of 65 meters below the surface. One of the rooms is the widest in Belgium. The dimensions are impressive: 200 x 35 x 10 meters. The Caves of Hotton are the only caves in Belgium to be granted protection and heritage status. Temperature inside the caves remains constant at 12°C. Colors vary from sparkling white to deep red. Stalactites, stalagmites, and the awesome sound of water dripping on the rock create an otherworldly impression.