Machines or other technology that has laid unused for thousands of years yet are still more or less operational.
Alternate name: Ancient technology
The first video game about Ancient machines was released on November 18, 2008.
Considering that modern technology naturally corrodes, rusts, and otherwise falls to ruin in only a decade or few if not actively maintained, this obviously tells of supreme craftsmanship and materials, though commonly the time difference is ignored (e.g. no matter how treated a wooden waterwheel is, it won't survive hundreds of years, especially without maintenance).