Here is 1 or 2 hidden gems at WDW from an older thread. If anyone knows the original author please chime in so I can give proper credit. If anyone has any more or knows if something on this list no longer exists please let me know so I can edit this list.
Magic Kingdom
1. Cinderella’s Royal Table: Gus and Jaq are looking down over the foyer.
2. Tony’s Town Square: Paw prints of Lady and the Tramp outside of the porch on the sidewalk.
3. Hall of Presidents: Bill Clinton is the only president to wear a Mickey Mouse tie.
4. Buzz Lightyear’s Space Ranger Spin: Some of the biggest point values are in the first room. Turn around and hit the back of the orange robot’s arm or the back of the buzz saw…. 100,000 points.
5. Buzz Lightyear’s Space Ranger Spin: When you are in line the "story" of the attraction is unfolding. Once inside, all guests are being 'shrunk' to toy size so they are able to fit in the xp 37-space cruisers. This is why, once you get up to the Viewfinder and Magna Doodle and Buzz, they are all the same size as you. Then when the ride is over and you see Buzz telling you your scores and zurg behind bars, you return to normal 'human' size.
6. Haunted Mansion: The top of the building looks like chess pieces. The only one missing is the knight. (It’s inside)
7. Haunted Mansion: In the wire fencing around the mansion there are 999 stick people made out of the wire in the fence.
8. Haunted Mansion: Ballroom Scene: the men are leading the ladies.
9. Haunted Mansion: As soon as you enter the graveyard, you go under a tall gate, if you look really hard, at the top left-center portion of the gate, there is a paper tag. This is the original purchase tag from California, they forgot to remove it, and it is still there today!
10. Haunted Mansion: In the scene with the lone piano player, pay close attention to what's going on outside! Notice the direction the wind is blowing the tree compared to the direction the clouds are moving...
11. Haunted Mansion: In the endless hallway there is a chair with a Hidden Donald Duck embedded in it.
12. Haunted Mansion: As you exit look in the pet cemetery for a statue of Mr Toad.
13. Market House on Main Street: Go to the back of the store and look for an old fashioned phone. It’s called the Gossip Phone. Pick it up and listen to it.
14. Center Street off of Main Street: go to the end of the street and listen carefully, you can hear tap dancing and singing lessons going on upstairs.
15. Many Adventures of Winnie the Pooh: In the first room there is a picture of Mr. Toad handing over the deed to Owl.
16. Under the Train Station: Keep your back to the castle and look up. In the rafters you can see some Disney character “items” left behind.
17. Main Street: After the afternoon parade goes by, watch the upstairs windows, they will close automatically. That is where some of the music is piped.
18. Behind the castle and to the left is a fountain with Cinderella. When children look at her (from a shorter perspective) it appears as if she has a crown. Adults need to bend (or bow) to her in order to see it too.
19. Liberty Square: there is a gate around a door. It guards a marble slab that used to be a step at Monticello. Jefferson actually walked on it.
20. Magic Carpets of Aladdin: there are embedded jewels in the concrete around the ride.
21. Casey's Corner: I was sitting in the bleachers facing the TV showing Disney sports cartoons. On the same wall as the bleachers, there is a bunch of old baseball pictures. One in particular caught my attention. It seemed a lot newer than the other pictures-it wasn't really grainy at all, yet it was dated "1915." Also, the players were sitting on very modern-looking metal bleachers. The last thing I noticed was...THEY WERE ALMOST ALL WEARING PRECISELY THE SAME MOUSTACHE! Could these be the Imagineers who did the Casey's corner rehab a few years back? If you want to find it yourself, go in the TV room connected to Casey's Corner. The pictures are just inside the doorway, on the wall to the left. The picture I'm talking about is about at eye level.
22. Tinkerbell’s Treasures: Try to find Tinkerbell flitting around the store.
23. Tom Sawyer’s Island: Try to find one of the paintbrushes, and bring it back to a CM for head of the line passes.
24. Sir Mickey's Shop in Fantasyland: look at where the roof meets the walls. You will see Willie the Giant from Mickey and the Beanstalk peeking into the shop.
25. Liberty Square: The sidewalks are brown but the streets are not. People in that time dumped garbage out the windows, so Disney made it appear dirty.
26. Liberty Square: all the shutters on the windows are hanging crooked. This is because in those times leather was used to fasten shutters on and would stretch over time to hang crooked. The Imagineers used crooked metal fasteners.
27. Walt’s name only appears on one window on Main Street. It is the one above the ice cream parlor and is the only one that faces the Castle.
28. There is a silver plate that runs between Liberty Square and Frontierland. This plate represents the Mississippi River, separating the east from the west, and there is water flowing out from the plate into the Rivers of America. Additionally the buildings also reflect changes east to west from the colonial style to the frontier boomtown to the southwestern adobe buildings.
Epcot
1. Electric Umbrella: Look for the talking trashcan and the talking water fountain.
2. In Epcot, if you stand in the correct spot, you can see the Tower of Terror appear to be part of Morocco. The best spot to see it is near the souvenir stands between Future World and World Showcase, specifically the souvenir stand closer to Mexico. And since both have similar colors, they blend together decently.
3. Journey Into Imagination with Figment: as you are about to go into the sound room, look at one of the doors, it says Dean Finder(Dreamfinder). Also, in the finale, look to the Figment with the music book glider, there is a Dreammobile.
4. Mouse Gear: look for the blimp from the original JII, sans the balloon.
5. Spaceship Earth: the scene with the monks writing. One has fallen asleep and has a Mickey shaped ink blob next to him.
6. UK pavilion: there is a path running down the side of the Rose & Crown pub, which leads to a 'secret' garden.
7. Maelstrom: When boarding the boats look at the Vikings, one is wearing Mickey Mouse Ears.
8. Watch out for the rock formations on the shores of the Canada pavilion during Illuminations: Reflections of Earth. For the fireworks show, one of these boulders "breaks open," rising up into the air, a contoured piece of rock topping a pole equipped with lights and speakers for the show. Once Illuminations ends, the pole silently retracts back into the boulder, its rocky top preserving the appearance of the Canada shoreline. It's all part of Disney's attempt to preserve show elements--outside of show time, you'd never know it wasn't a real rock. A similar pole rises out of the rocks at the Japan pavilion, and two light poles are cleverly concealed in the Italy pavilion
9. Germany: The stone "castle" building, located in the Germany pavilion alongside the Biergarten Restaurant, was to have been the home of a Rhine River cruise attraction taking guests on a boat ride through the German countryside. But the attraction was never built. The main entrance to the ride would have been located at the back of the Sommerfest Outdoor Café.
Disney Studios
1. Tower of Terror: Look for marquee with missing letters, on the bottom, the fallen letters will read “Evil Tower U R Doom”. Sadly this has been removed.
2. Muppet Vision 3-D: Outside of the building there is graffiti written all over, stop and read the sometimes humorous messages.
3. Muppet Vision 3-D: Look for the key under the mat when entering the theater.
4. Indiana Jones Epic Stunt Spectacular: Outside of the theater there is a well. Pull on the rope that's dropped inside of the well and listen.
5. Indiana Jones Epic Stunt Spectacular: There are crates stacked in the bushes that say “don’t open”… Go ahead and open them.
6. Singing in the Rain Umbrella: Near Lights Motor Action at the end of NY Street. (Or whatever it’s called now)
7. Honey I Shrunk the Kids: Look for the dogs nose and stick your hand in its nostrils, it will sniff you (and sometimes sneeze!).
8. AFI shop at the Back Lot Tour ride: look for the area nearby which is stacked with wooden crates, open them and you will be rewarded with various silly effects.
9. Look for the snowman in MGM. Great photo op!
Animal Kingdom
1. Look for “DeVine” a real human vine, usually “hanging around” near or behind the Tree of Life.
2. Tusker House: sit outside on the back patio area when you eat and listen carefully. You can hear people upstairs who seem to be having trouble cleaning.
3. Tamu Refreshment Stand: Behind it is a half wall where a meet and greet takes place. The paint is chipping and one area of chipped off paint is a hidden Baloo.
4. Kali River Rapids: go on the bridge and find the buttons that allow the two elephants below squirt the riders.
5. Dinoland Playground: Try to open the door.
Downtown Disney
1. Downtown Disney Marketplace: go with your children and ask at one of the (Disney) store cash registers for the Sticker Hunt booklet. There are 15 different stickers to collect at each of 15 stores.
2. Art of Disney store: They run a quiz every day and give out prizes if you get them all right!
Resorts
1. Contemporary Resort: near the Monorail loading dock, there is a huge mosaic. Look for the 5 legged goat within that mosaic.
2. Port Orleans: the musical notes attached to the check in counter translate to “When the Saints Go Marching In.”
3. Fort Wilderness: Look for the lawn mower tree.
4. Wilderness Lodge: Has a smokehouse tour.
5. Wilderness Lodge: Get a hidden Mickey list and go on a hunt!
6. Wilderness Lodge: Go look for Old Faithful.
Everything Else
1. Monorail: Sit up front with the captain and get a co-pilot’s license.
2. Watercraft: take the boats or ferries and get a Disney Watercraft sticker.
3. Ask for a list of Hidden Mickey’s from Guest Relations.
4. Ask for a list of Pressed Pennies from Guest Relations.
