I saw these words "Quid Aere Perennius" somewhere. Where was I and what do the words mean and what is their original source?

You were probably standing outside the town hall of Waterford, Connecticut. Their town motto, "Quid Aere Perennius", means "What is More Lasting Than Brass", and is inscribed in marble above the City Hall entrance.

https://www.waterburyct.org/content/9586/9599/9601.aspx

forgot to include the origin. From the same source,

'It was inspired by Horace's Book III, Ode XXX: "I have executed a monument which is more lasting than brass and more sublime than the regal elevation of pyramids which neither wasting the shower, the unvailing north wind, or an innumerable succession of years and the flight of seasons shall be able to demolish."'

The original Latin is from Horace's epilogue to the publication of the three books of Odes he published in 23 B.C.; because I'd feel I would have wasted 11 years of Latin study, I included my own translation. Horace always was a favorite...

I got the Latin from my copy of Daniel Garrison's excellent annotated edition of the Epodes and Odes, but here is a link to the online text (Ode XXX is at the very end): http://www.thelatinlibrary.com/horace/carm3.shtml

Exegi monumentum aere perennius
regalique situ pyramidium altius,
quod non imber edax, non Aquilo impotens
possit diruere aut innumerabilis
annorum series et fuga temporum.

I have completed a monument more enduring than brass
and taller than the royal ruin of the pyramids,
which neither the devouring rain, nor the violent northeast
wind
shall be able to scatter, and which the succession
of innumerable years and the flight of time shall
not be able to overthrow.

I only studied Latin for 6 years, but definitely think your translation is more elegant than the onee given at my link! Now that I read theirs more carefully, it is a pretty dreadful effort, with a couple of basic errors.

Its a real shame that today Latin does not get the respect it deserves.

Most students would rather play video games.