Closing the hole
It is believed that this phenomenon is the result of a strong pressure that forces oxygen and hydrogen atoms out of the rock. The water created by this chemical reaction has nowhere to go and is therefore trapped underneath the surface. This discovery was met with astonishment in scientific circles. We might never have discovered this without the Kola Superdeep Borehole.
The closure of this gap occurred around the same time that the Soviet Union fell. In 1995, the scientific project was permanently halted. Today, the hole is primarily seen as an environmental hazard, as it provides direct access to the unstable depths. Interested parties can admire the remains of the experiment in a museum in the town of Zapolyarny, about nine kilometers away.