Fringe Connections

The bus in "The Ghost Network" was ambered. Huge sections of cities were ambered in the Redverse in "Over There (Part 2)".

The crane that crashed during the intro has a Massive Dynamic logo on it.

The butterfly glyph can be seen as Olivia and Shapeshifter Charlie fight in the alley.

Cecil mentions the Observers using a light bomb in "Through the Looking Glass and what Walter Found There", which is what Loyalists threw at Peter in the sewer tunnels in "The Bullet that Saved the World".

The Child's happy expression drops when he sees the Observer.

The seahorse glyph can be seen on a door in the pocket universe.

The ship at the end of "Nothing as it Seems" showed the creatures from "Snakehead".

The Redverse traded Alt Broyles for Fauxlivia by cutting off one of his legs to make their masses equal.

The butterfly glyph can be seen near Lincoln in the rail yard.

The hallucinogenic drug from "The Dreamscape" was used as a weapon against the Observers in "An Enemy of Fate" to make them think they were being attacked by butterflies.

The opening crawl is an homage to Blade Runner.

A frog can be seen in Walter's Monty Python trip.

The End-of-Dayers used light bombs called Electrilights in "The Day We Died". Loyalists threw a light bomb at Peter in the sewer tunnels in "The Bullet that Saved the World".

Nick Lane's wardrobe is all dark colors like Olivia's.

A seahorse can be seen hanging from the taxi when Walter listens to music.

William Bell had a bell on his desk in "There's More Than One of Everything" and rang it after he introduced himself to Olivia. He left a similar bell to Nina in his will in "The Box".

The flower glyph glitches away after the scene where Olivia's fear caused her to interrupt all the electronics in the room.

A seahorse can be seen on Peter's luggage.

In "The End of All Things" September said that he made a mistake when he distracted Walternate in his lab in "Peter" and saving Walter and Peter from the icy lake was an attempt to rectify that mistake.

Olivia pulled up a list of the frozen heads found in S02E04 'Momentum Deferred' and they were all marked with "2E204", a reference to the episode in which they were stolen.

A hand can be seen on the wall when Olivia and Peter attack the Observers and Loyalists.

Fauxlivia studied old Fringe cases for intel in "The Box", including Olivia's taped testimony from "Dream Logic".

The episode opened in "Manhatan", seemingly a typo but actually signifying this was an alternate Manhattan.

A hand can be seen outside the entrance to the daycare center.