Money might not buy you happiness or love, but it does mean you can put money into outlandish projects that won’t turn a profit. That may be why Amazon founder Jeff Bozos is helping finance a clock that’s designed to work for 10,000 years. Oh, and it’s in a cave.

The clock was first conceived by parallel computing inventor Danny Hillis in 1995 and is designed to both find a creative use for technology and make humans think about the big picture of time.

The concept of the clock is on a massive scale in four-dimensions. It has a 10,000 pound pendulum at the end of a 200 foot pivot, and will be housed in a 500 foot shaft in a remote Texan mountain owned by Bezos. Rather than ticking every second, it ticks once a year. The only hand advances once a century. And there’s a cuckoo that appears once every millennium.

The theory is that sunlight power will be enough to make sure the clock continues to keep time. There is also a display of the precise time and a daily chime, but these only operate if and when somebody winds a mechanism. Whenever this happens, the daily chime will play a different melody every day for each of the thousand years.

The winding isn’t likely to be a daily occurrence though: visitors will need to get to the town of Van Horn (population 2,435) and then hike for around a day before making their way through tunnels and chambers.

As well as the clock, they’ll see five underground rooms. The first will, one year after the clock goes into motion, house an animation of the solar system and all the interplanetary craft mankind launched during the 20th century. The second is scheduled to have an animation to mark the 10th anniversary of the clock, though the content is yet undecided. Both animations will play once a year, with the clock providing the power.

The remaining chambers are designed to commemorate the 100th, 1,000th and 10,000th anniversaries: the project creators will leave mechanics in place for future generations to create clock-powered animations.

Though a small-scale prototype was first produced in 1999, the project has now reached the stage where the design is complete and construction is underway: completion is scheduled simply for “many years into the future.”