No, Chicago is not being invaded by monsters with giant heads. Situated in Millennium Park, this unique fountain is a cross-section of city life and digital art. Oh those fancy artists and their wacky inspirations. I'm guessing the inspiration for this fountain involved cubes. Lots of cubes. I'm just guessing here.
The hotspot in-game is referenced to the actual exhibit in the Millennium Park in Chicago, where an artist captured video of 1,000 faces in Chicago and plays them back on the exhibit itself (hence the name "Face Fountain"). Each piece, while showing a short 10 second clip of a person's face, also shoots water out from where the person's mouth is located.