The richest man in the world, Jeff Bezos, keeps pretty busy running the Amazon empire.

At any one time, the online shopping conglomerate usually has a few exciting projects in the works. Amazon Go, the grocery store without checkouts opened to the public earlier this year. Amazon Key, the delivery service that lets drivers into your house, is still being rolled out.

But now, Bezos has a new project that does not really relate all that much to online shopping. The billionaire has commenced work on the 10,000 Year Clock - a giant timekeeper that will be housed inside a mountain in the United States.

The name is based on the clock remaining accurate for the next 100 centuries. Instead of telling the time in hours, minutes and seconds, it records years and millennia. The clock will only tick once a year and the small hand will only shift once per century.

And, it is a cuckoo clock, but keeping with the theme it will only make a sound once every millennia - 10 times in its life.

Bezos will spend $42m (about £30m) to build the clock in the Sierra Diablo mountains in Texas. People are welcome to visit the clock once it is built, but it is a several-hour drive from the closest airport and then a hiking trail that rises to 2,000ft above the valley.

The clock was not Bezos' idea. In a tweet revealing the works, he credits "the genius of Danny Hillis, Zander Rose and the whole Clock team".

But why spend so much money building a yearly clock? Bezos and the people behind the 10,000 Year Clock want to get people thinking about the length of time and how small an individuals life - in comparison - is. They are hoping that people will respect Earth's environment once comprehending how long the planet must survive.