HOLE TO HELL : Kola Peninsula of Russia.

The Kola Superdeep Borehole, situated in the depths of Earth, is considered as the gateway to hell by some. This manmade hole, which stands at a depth of 40,230ft (12.2km), is the deepest artificial point on Earth. Despite the Soviet's nearly 20 years of drilling, the project was discontinued in the aftermath of the Soviet collapse, leaving the drill bit only one-third of the way through the Earth's crust to the mantle.

In the era of the Iron Curtain, the Soviet Union's claim of finding free water at the drilling site was met with skepticism by Western scientists who believed the crust was too dense to allow water permeation. The competition between the Soviet and German boreholes was further fueled by the Soviet's lack of data openness.

Now, with new technology and advanced knowledge, scientists aim to obtain actual samples of the Earth's mantle, which is 1,800 miles deep. The mantle's properties today can only be studied through close-to-surface sites like Oman, but these are limited to only ancient samples. In comparison, rock samples obtained from superdeep boreholes would offer invaluable insight into the Earth's inner workings.

The Earth's crust, which is the outermost layer of the planet, is only 25 (40km) miles thick. Beyond that lies the mantle, followed by the Earth's core at the center. The race to explore this "deep frontier" was a demonstration of technological and scientific advancement, similar to the space race. However, unlike the space race, there was no clear winner in this exploration of uncharted territories.

The Kola Superdeep Borehole is considered by some to be the gateway to hell, due to its depth of 40,230ft (12.2km). It is the deepest man-made hole on Earth, and the deepest artificial point. Despite almost 20 years of drilling by the Soviets, the drill bit had only reached one-third of the way through the Earth's crust to the mantle when the project was abruptly terminated during the post-Soviet era.

Uli Harms, of the International Continental Scientific Drilling Program, recalls the competition between the Soviet and Western scientists during the Iron Curtain, and mentions that the Russians were secretive with their data. However, the initial claims of finding free water at the site were met with skepticism among Western scientists, as it was believed that the crust was too dense to allow water penetration at such depths.

Sean Toczko, program manager for the Japan Agency for Marine-Earth Science, explains the ultimate goal of the project, which is to obtain living samples from the mantle. Unlike in Oman, where mantle close to the surface can be found, the samples from the Kola Superdeep Borehole would represent the mantle as it currently exists, similar to the difference between a live dinosaur and a fossilized bone.

The Earth's crust is like the thin skin of the planet, only 25 miles (40km) thick, and it covers the 1,800-mile deep mantle, which in turn surrounds the core at the center of the Earth. The race to reach the unknown "deep frontier" was similar to the space race, as it showcased the capabilities of cutting-edge technology and engineering. The rock samples from the Kola Superdeep Borehole had the potential to be as important for science as anything brought back from the moon, although in this case, no one truly emerged as the winner.