Tent city? Tent arcology? this is a modular tent system called the "Decagon Link Station" by Japanese camping company Logos.
Fortunately, you don’t need to spend a fortune in a modular extensible tent system to make such a set up. The same concept applies — you can use the zippers of two tents (that hopefully match, tents within the same brand should usually have same size zippers, but a little hacking with tools should make things compatible) and zip them up! Crafty and handy with tools and such? Make your own tunnel/four way/different modules and interconnects!
In short: zip up two or more commercial tents or create your own tents and build a large interconnected structure!