John Cage recital set to last 639 years recently witnessed a chord change

> The Long Now foundation built a clock to last 10,000 years

The Long Now Foundation is attempting to build a clock to last 10,000 years.

Construction began close to a decade ago, and there is no estimated completion date. Construction of the clock may well last 10,000 years.

I think at one point the Van Horn TX clock was considered a "prototype" or another one that would be built incorporating lessons learned, although I don't know if that's still the plan.

Coincidentally the clock will ring with a cycle of chimes that repeats every 10,000 years

> The Long Now Foundation is attempting to build a clock to last 10,000 years.

The pyramids are only half that old, and they've accumulated a fair bit of damage despite being solid stone.