Last night was the official debut of the new American Underground @ Main campus in downtown Durham. And I never would have guessed who I saw there, but I’ll get to that in a minute.

First, about the space: It’s 22,000 square feet, largely in a well-furnished basement like its sister campus, now dubbed Underground @ American Tobacco, but with a warmer feel. There’s a supersonic slide that lives up to its name, offices for small teams, smoffices (40 square foot workspaces) and a 3,000 square foot coworking space.

For the debut party, it was dressed up very nicely with a jazz band, a couple of bars, and local food spread throughout. The space wasn’t designed for throwing parties, though; it was designed to house startups and help them grow.

Last Friday, Saturday, and Sunday during Triangle Startup Weekend I spent about 25 non-party hours in the space while helping out at the event. Once TSW got rolling, there was a lot of down time, so I brought my laptop and basically spent the weekend coworking from the new campus. No party, just in the space working on my startup, surrounded by a bunch of other people working on their startups.

During this time, I noticed a few things. There are outlets about every three feet, there’s a whiteboard almost anywhere there could be one (an entire wall in the coworking space is a whiteboard) there’s a kitchen and meeting rooms of varying sizes, and you don’t really feel like you’re in a basement— if you do, you can go to the main level which is above ground.

The chairs in the coworking space are unbelievably comfortable, too. Who cares about the chairs? You will when you sit down to work for 16 hours straight.

It’s a great place for working startups—the experience of those who designed it shows.

It’s also fit to house 50 startups (40 already call it home) plus coworkers, so there’s ample opportunity for interaction with other entrepreneurs. And this aspect— the creation of a close proximity community— is what allowed me to bump into a blast from the past last night.

Mark Belk works at a startup based in American Underground @ Main, but until last night I had no idea. I know him from years ago when I was a student waiting tables at a local grill, and he was a man in the restaurant industry. Now he works at ShiftZen, a company that makes employee scheduling software for the restaurant industry. It was great to see him and learn about his company, but we were both surprised at the context.

My interaction with Mark was possible because the space brought us together. I took notice of it because it surprised me, but the value of it is that we ran into each other and were able to talk startup. I also got to talk to startup with about half a dozen other people like Tobi Walter of Shoeboxed, Andrew Pearson of Windsor Circle, and Fitch Carrere of PopUp.

A campus with affordable, functional space that attracts startups creates these opportunities. And if your company is based there, it creates them every day.

In April, I wrote about the importance of the startup advisory network, which includes not only mentors, but also more casual advisors and entrepreneurial friends who can provide feedback. I also mentioned that organic development of these relationships and frequent face-to-face interaction typically produces the most value.

A campus like American Underground @ Main gives entrepreneurs ongoing access to a casual advisory and feedback network of 40 startups and growing. And this potential network is as accessible as it gets—you work next to them each day and run into them in the bathroom.

Between creating this network effect and providing such a significant amount of startup space and amenities, American Underground @ Main is a very big step forward for the Triangle’s startup environment.