Where Is the Deepest Hole in the World?

Humanity dug the deepest hole in the world over 20 years, but it still reached only 0.2% of the way to the Earth's center. The project began as a secret rivalry between the United States and the Soviet Union. The U.S. abandoned the effort after drilling just 182 meters, while the Soviets continued for a full two decades, not for minerals or oil but to reach the Earth's mantle. They ultimately reached a depth of 12,226 meters—longer than Mount Everest and deeper than the Mariana Trench. The extreme heat caused drill bits to melt, yet the endeavor yielded 2‑billion‑year‑old fossils and laid the groundwork for modern drilling technology. Today, Japan has begun drilling into the ocean floor, where the Earth's crust is thinner.