1.At the beginning of Up, as we watch the years pass by, the town beyond the hill grows into a bustling city.
2.According to Pete Docter, Up's co-creator and director, Carl was designed to look particularly square, especially his head and glasses, to symbolize his stubbornness and confinement within his house. Russell, on the other hand, was made to look more rounded, like a free and buoyant balloon or a spinning top.
3.And this rounded vs. square aesthetic goes beyond just Russell and Carl. It can also be observed with Ellie and Carl, and with all of their respective possessions. Ellie was a source of vivaciousness and vibrance in Carl's life, so her aesthetic was rounder.
4.And you might also have noticed that when Carl was a young boy hungry for adventure and excitement, he looked just a little bit rounder than he does as an old man.
5.Speaking of young Carl, did you notice that he and Russell each had a single collar tip popping out? Clearly they're kindred spirits.
6.Ellie makes Carl cross his heart and promise he'll make it to Paradise Falls. When Carl and Russell first meet, Russell offers to help Carl cross the street so he can earn his "Assisting the Elderly" Wilderness Patch. When Carl declines, Russell says, "Well, I gotta help you cross something" — and he does. He ultimately helps him fulfill the promise he made to Ellie.
7.Carl and Ellie spend their wedding day hammering nails and sawing wood, which, for all the adults out there, is a popular euphemism for having sex.
8.Try not to cry, but as Ellie hands Carl their adventure book for the last time, you can spot the tape and markers on her bedside table.
9.Ellie's character was also represented by the color pink (scroll up, you can't miss it). When Carl returns home after her funeral, the pink slowly fades from the shot, leaving the house dark and gray.
10.Carl still receives "Venezuela Tourist Info" in the mail from when he bought tickets to go with Ellie — a cruel reminder of the trip they never got to go on together.
11.On the day they set sail, the antenna is notably missing from the roof of the house. This is because it was removed so it wouldn't pop any balloons.
12.And if you look veryyy closely, you can spot a bunch of helium canisters on the front lawn.
13.You can also spot Lotso the Bear from Toy Story 3 when the house is taking flight.
14.Dug succeeds at tracking down Kevin because he's a golden retriever, a sporting breed that specializes in tracking birds. The dogs who tried and failed to track down Kevin — a Doberman, a rottweiler, and an English bulldog — are all guard dog breeds and therefore not bred to be good trackers.
15.The villain in Up is named Charles Muntz. Not-so-coincidentally, a film producer by the name of Charles Mintz is best known for stripping Walt Disney of the ownership rights of his very first successful creation, Oswald the Lucky Rabbit, which drove Disney to create his very own animation studio.
16.And just before the credits roll, Russell, Carl, and Dug are calling out the colors of passing cars and Dug calls out "gray one" — a joke about the common (though disputed) perception that dogs are color-blind.