In the Sierra Diablo range, located west of Texas, a unique project known as the 10,000-Year Clock, or the Clock of the Long Now, is being built. This ambitious timepiece is funded by Jeff Bezos through his private investment firm, Bezos Expeditions, with a total investment of $42 million. The clock is situated on land owned by Bezos in the Sierra Diablo mountains, more than 150 kilometers from the nearest airport. The site remains private, and no official completion date has been announced. Once completed, the clock will be buried in limestone and will feature a massive underground structure that extends 152 meters deep. A key part of the design is its century hand, which only moves once every hundred years. The idea for the clock was first proposed in the late 1980s by computer scientist and inventor Danny Hillis. The project was formally launched in 1986 with the goal of encouraging people to think about the long-term future of civilization. The clock's design is intentionally out of sync with typical human timekeeping: it only ticks once a year, its century hand advances once per century, and a mechanical cuckoo will emerge every millennium. The structure is built around a vertical shaft carved into raw rock, 500 feet deep (about 150 meters) and 12 feet wide (approximately 3.6 meters), forming the core of the clock’s mechanism. When finished, the clock will be 500 feet (152 meters) tall and powered by natural thermal cycles. It will include a carillon generator designed by composer Brian Eno, which will play a different melody each day for ten thousand years. This carillon is a mechanical computer that uses an algorithm to choose from millions of possible musical sequences, ensuring that no melody repeats for more than ten thousand years. The clock will be powered by the temperature difference between day and night, using thermal expansion to lift heavy weights. A synthetic sapphire window allows sunlight to enter, creating a thermal gradient that drives the mechanism. To maintain the clock's operation, the design includes a secondary winding mechanism that allows people to wind it by hand. This feature was intentionally included to connect the clock to human interaction. Without this manual winding, the century hand would remain stationary. The materials used in the clock’s construction are carefully selected for their durability, including marine-grade titanium, ceramic, and stone, as well as marine-grade stainless steel, to resist corrosion and rust over ten thousand years. The clock will also feature five commemorative chambers, each marking a milestone: the 1st, 10th, 100th, 1,000th, and 10,000th anniversary. These chambers are meant to be filled by future generations, ensuring the clock’s legacy continues over the centuries.