Production has begun on Amazon CEO Jeff Bezos’ $42 million project to build a mechanical clock that will last 10,000 years.

Danny Hillis, the man behind the idea, first talked about building a clock that would last 10 millennia in 1995, according to Longnow.org.

“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. I want the cuckoo to come out every millennium for the next 10,000 years,” he wrote.

He went on to co-find the Long Now Foundation, a nonprofit, to make his idea a reality.

The 500-foot-tall clock is being built deep in a mountain in western Texas.

Bezos has put $42 million into the project because of his belief that “humanity” needs to invest in its future.

“We humans have become so technologically sophisticated that in certain ways we're dangerous to ourselves. It's going to be increasingly important over time for humanity to take a longer-term view of its future,” he said, according to Business Insider, which cited a 2012 Wall Street Journal article.

Bezos told Wired in 2011 that he thinks the clock will outlast the United States: “Over the lifetime of this clock, the United States won’t exist. Whole civilizations will rise and fall. New systems of government will be invented. You can’t imagine the world — no one can — that we’re trying to get this clock to pass through.”

While there is no scheduled completion date, the foundation’s website notes, it will be open to the public as soon as it’s ready.