Jeff Bezos is building a giant clock inside a mountain to keep time for 10,000 years. It costs $42 million.

While most of us use clocks to plan our daily routines, a massive timepiece inside a mountain in West Texas is designed to track time for the next 10,000 years. Known as the "10,000 Year Clock," this ambitious project began as the vision of computer scientist Danny Hillis, but it's now being brought to life by Amazon founder Jeff Bezos.

The billionaire decided to commit $42 million to this clock-making project. “I want to build a clock that ticks once a year. The century hand advances once every 100 years, and the cuckoo comes out on the millennium. If I hurry, I should finish the clock in time to see the cuckoo come out for the first time,” Hillis wrote in a 1995 opinion article for the WIRED Magazine. Thereupon, he partnered with environmentalist and writer Stewart Brand and founded the Long Now Foundation, a nonprofit that aims to “foster long-term thinking,” per IFL Science.

The giant 10,000-year clock is hundreds of feet tall and consists of five room-sized anniversary chambers that will display times for 1-year, 10-year, 100-year, 1,000-year, and 10,000-year anniversaries. A special orrery is designed to include the interplanetary probes launched to other planets and Earth’s Moon. There is also a chime generator composed of dials and steampunk-style gears, designed to create a different bell-ringing sequence each day for 10,000 years.

Powered by solar energy, the clock’s heart is a titanium torsion pendulum that beats once every ten seconds, according to Bloomberg. Another interesting feature of the clock is that its display doesn’t become active unless a human enters the clock chamber and triggers the winding mechanism. This clock will tick once a year, chime every century, and its cuckoo will emerge every millennium.

The clock, as per Bloomberg, is deliberately constructed with inexpensive materials, precisely to discourage looting. Plus most components are designed in such a way that they can be repaired by mere Bronze Age technologies and tools. While the team started the excavation on the mountain in 2012, the installation was kicked off in 2018, as Bezos also posted on X, describing the clock as "all mechanical, powered by day/night thermal cycles, synchronized at solar noon, a symbol for long-term thinking."

"It's a symbol for long-term thinking. This clock is meant to remind us that we should be thinking long-term about our children, their children and people thousands of years from now," Bezos explained in an episode of the Lex Fridman Podcast, per Benzinga. "It's in a remote location to protect it and make visiting it a pilgrimage. It's about long-term thinking," he added, referring to the clock’s remote location inside the Sierra Diablo Mountain Range.

Apart from Bezos, several partners have contributed their ideas and cash to the “10,000-year clock” project including Hillis’ company Applied Minds, The Long Now Foundation, Penguin Automated Systems, Swaggart Brothers, Seattle Solstice, and Machinists among others, according to clock's website.