Fringe Connections

In "And Those We've Left Behind" Peter picked up the same toy plane (perhaps not literally the same) that he played with in "Subject 13".

This episode reveals that there is more than one Observer. The intro sequence since the pilot episode has had a single frame that says "OBSERVERS ARE HERE".

The seahorse glyph can be seen on the back of one of Markham's books.

The radioactive isotope compound from "The Cure" that caused heads to explode was used as a weapon against the Observers in "An Enemy of Fate".

The license plate on Olivia's SUV reads 1R2D21, and the licence plate on Broyles's SUV reads 1C3PO1.

The butterfly glyph can be seen on the wall in the diner where Olivia and Lincoln meet.

The Fringe team used the skin-growth toxin from "Ability" as a weapon against the Observers and Loyalists in "The Bullet that Saved the World".

Jones is working with Bell, who is alive.

A butterfly can be seen attacking Mark Young.

The Observers read Broyles' phone call from the impressions his sound waves made on the glass in his car in "An Enemy of Fate", like Peter did in to hear the phone call Nancy Lewis made in "The Road Not Taken".

There is a Massive Dynamic logo on Flight 627's engine.

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

Walter used the clapper to turn on the lights in "In Absentia". He installed it in "Midnight".

The briefcase contained photos of Walter.

The leaf glyph is on the electronic keypad at Massive Dynamic.

Walter implanted a tracker in his neck in "Snakehead" which is used in "Grey Matters".

The Fringe team is part of a full-fledged branch of the Department of Defense in the Redverse.

A frog can be seen on the dock when Walter is high.

In "The Human Kind" Walter tested the Observer tech implant on the brain of the Porcupine Man from "Nothing as it Seems".

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

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

In "And Those We've Left Behind" Astrid used the same wand to detect abnormalities that Lincoln used in the opera house in "Over There (Part 1)".

Donald entered the mine 5 weeks after the invasion and took some rocks. He was described as being in his late 30s, medium height, dark hair. Donald said he was waiting for "a colleague, a scientist from Boston, to meet him." Observers found him and took him away.

A butterfly can be seen on a lampshade near the front of Olivia's apartment.