4 ms·

5-10 years is the classic naive/huckster estimate. 30-50 years is the respectable man's "I have no idea" estimate for anything.

• jpadkins 11y ago
  We used to build cathedrals that took 3 generations of masons. Imagine working on a design that your granddaughter would see the launch of...
  • eru 11y ago
    Look at the Sagrada Familia in Barcelona. They started building in the 1880s, and it's still going on.