Amazon's Jeff Bezos just revealed video of a massive 10,000-year clock that's being built inside a West Texas mountain.

The clock is 500 feet tall and powered by the Earth's thermal cycles, Bezos said in a tweet Tuesday.

"It's a special Clock, designed to be a symbol, an icon for long-term thinking," a blog post signed by Bezos says.

The clock has been in the works for nearly three decades, according to the post, and is designed to tick once a year. The century hand advances once every 100 years, and the cuckoo comes out on the millennium.

The project was initiated by Danny Hillis in 1989. Bezos said he's been "helping Danny with the project for the last half dozen years."

"Building a Clock inside a remote mountain is a big task. Construction is under way, and we're making progress every day," the post reads.