10,000-year clock

The 10,000-year clock is an accurate, long-term mechanical timepiece designed to tick once a year for 10,000 years. The timepiece is also referred to as the Clock of the Long Now and is located in the Sierra Diablo Mountain Range in West Texas. The device features a century hand that advances once per 100 years and a cuckoo that emerges on the millennium. The first functional prototype of the clock was built on December 31, 1999, in time to display the rollover from 1999 to 2000 and chime twice.

While the design does not require a power source, it does require “winding" by way of lifting a weight. Because it was designed to require occasional human servicing, this was not seen as a major barrier to long-term function. The clock also harnesses changes in temperature in its mountain location to create power, which allows it to keep track of time for extended periods without  winding . Accuracy is maintained by synching with the sun.

The clock was designed under design principles favoring longevity, maintainability, transparency, evolvability  and  scalability. Design considerations for reliability included a transparent casing for observation of mechanical function while in operation. The open design makes it easier to understand the device and thereby improves serviceability. Serviceability was also enhanced with simple low-cost materials and the low-technology requirements of bronze-age tools. Low-cost tools also ensured that parts would not be looted. The clock does not display hours or dates, a consideration of the fact that the design common in current systems, which measure these smaller increments, may change over the timepiece's long lifespan.

The design was created by Danny Hillis in 1986, and a full-scale prototype was initiated by Amazon CEO Jeff Bezos at a cost of $42 million. As much a marvel of engineering as a time-measuring device, the clock is part of the Long Now Foundation, an organization dedicated to long-term projects such as the well-known Rosetta Project that seeks to preserve the world’s languages. Installation of the clock began in February 2018.