From the website:

"It just takes once.
Once you've roamed our sun-spattered sidewalks ...
Once you've lost yourself in our vast city park ...
Once you've seen the fresh, young faces at our award-winning school ...
Once you've met our friendly residents and shopkeepers ...
Once you've been here for five minutes, you'll know you're home at last."

The sign in the window asks people to help save the building. It's the Welo building, and once had an opera house. More here.