The taxi that Olivia commandeers in the alternate universe has a rooftop ad for the Broadway show "Dogs" (instead of "Cats").
The alternate Manhattan headquarters for Fringe Division is a several story oval building with a hint of Roman Colosseum and a roof garden. The building is actually the central branch of the Vancouver Public Library.
The Observer passes next to Henry's taxicab shortly after Olivia enters the park where she expected to find the parallel universe's version of Massive Dynamic.
The glyphs in this episode spell out: AMBER
This episode takes place almost entirely in the alternate universe, referred to by fans as the redverse. To reflect this, the opening credits are red instead of blue as it is for regular episodes taking place in the prime universe (also called the blueverse).