Stargate?

This is a piece of art that a city selected to plop down in a median between busy roads, in addition to a number of other interesting works throughout the city.  But what if this piece of art was more than it seemed?  Maybe it's an ancient Stargate, or a portal to a magical realm, or allows people to 'slide' into a parallel universe.  Or, maybe it really is just a big, costly piece of taxpayer-funded art.  Write a little Flashy Fiction about it.