D&D 5E One Sentence to Describe a Metropolis

[R_J_K75]

There is an amazing tapestry of identities in a metropolis.

Im assuming that with people's suggestions I can piece together the ones I want to use and come up with different areas of the city. Right now I'm looking for help coming up with a short elevator pitch to present to the players on their journey there, revealing a bit more little by little the closer they get, then add more detail as they arrive and explore. Perhaps one sentence is too limiting but it'd be nice to come up with a single statement.

The Egyptians measured the value of goods and services in terms of a weight in gold, but never actually touched the gold (too sacred!). So, the "borrower" would pay off an IOU over time, by giving smaller items or services that the "lender" wanted later, until the equivalent value was paid in full.

This is a good description of how I envision transactions working.

 

[R_J_K75]

The 'old city' is buried under the new city and the new generations forget the ancient evil locked away, or how the winding passages of time created the labyrinth of tunnels and windings found right under their feet.

This reminds me of the Forgotten Realms Calimport supplement. IIRC the majority of the new city is built on ruins of the old one. Basically, as things got too old to use, they just built on top of it.

There's a TV show called "Cities of the Underworld" that I just saw is on Amazon Prime, maybe I'll watch a few episodes for ideas. I saw one on Rome I think that mentions it being similar to your suggestion.