The deepest hole we've ever carved out is just 9 inches across. It was started by scientists in 1970 and it took more than two decades to dig the record-holding hole.
So, how low did we go?
Drum roll, please. A whopping 0.2% of the distance to the center of the planet.
That's right, folks. The 7.5-mile-deep Kola Borehole in Russia barely managed to scratch the Earth's surface, never making it past the outermost layer of our planet.
Super high temperatures stopped the Russian scientists from going any farther. But, along the way they found some pretty cool things, like free water deeper than they ever thought it could possibly exist.
And 2-billion-year-old fossils from single-celled marine plants 4 miles below the Earth's surface.
Over two decades later, an international team of scientists is hoping to go deeper.
Despite a hefty $1 billion price tag and monumental engineering roadblocks, the goal is to go where no one has gone before. The mantle.