The flames were first spotted at about 10 pm at Stephen Leonard Park on T and 7th Streets.
Nearly 30 firefighters responded to the scene. Video shared by an ABC30 insider showed the intense flames.
It took fire crews about an hour to get the fire under control.
No one was in the building, and it appeared it was under renovation, investigators said.
The cause of the fire has not yet been determined. It's unclear if any future community events scheduled will be impacted.