Counter Strike amirite?
(Based on one of the smallest towns in the world.
Here's a video link:
This is a King of the Hill map with many vertical elements and flank routes.
It does feature tunnels though they are hard to avoid when you're basing it of that, though most of the middle is open.
This is a rotationally symmetric map).
Coober Pedy a3bb
Underground Australian Tiny Tunnels and Homes Hide Secret(s), Legend Speaks of Medals From 72 Hours.