Guess we could think of the Giza Pyramids as a counter-example. Plenty of religious monuments got built on the bones of slaves.

But I wonder, factoring out the physical toil, whether future generations might look at giant technological monoliths, maybe The Internet of 2100 and say;

   "Those techies were unhappy slaves. they laboured in basements and
    cubicles. They wrote code just to eat! It was obscenely inhuman."

Or maybe historians might pore through HN archives and say;

   "Those who believed in the Great Singularity", devoted their lives
   out of religious fervour. Many of them wrote code without being
   paid, just because they had a vision. "

Or maybe there will be no trace of us. Anyway, history can tell us facts about what happened, but maybe isn't so good at telling us what went on the minds and dreams of people past.

edit: s/Interest/Internet/g