Unseen locations

There are many Locations in BFDI, that have been mentioned by characters but never actually witnessed on-screen.

Announcer's Home
Announcer's Home is the place that Announcer and the Other Speaker Boxes presumably originate fom

Coverage
In Rescission, Announcer's Diary mentions that he isn't from Earth, implying he's from another world.

At the end of Return of the Hang Glider, the speaker boxes come to collect Announcer. It was actually mentioned for the first time when Teardrop Speaker Box says that BFDI wasn't a success and that Announcer must return with them and it was "time to go home."

Gem School
Gem School is a school that is gone to by certain gemstones, specifically only Diamonds.

Coverage
It was first mentioned by Pencil in No More Snow! when Pencil mentions to Ruby that pressing the red button and not the green button is something that should have been taught here. This causes Ruby to cry as she reveals that she never went to gem school. This, however, is only because this school is exclusive to diamonds, as pointed out by Book.

Burn Center
The Burn Center is a place mentioned by Four in Why Would You Do This on a Swingset, when asked where X was by Cloudy. It seems to be a place where one would go to recover from being burned or roasted. (In the sense, of being subjected to ridicule). X presumably went there because Four roasted him by telling him that at least he's "not the one that doesn't know their value"

Limb Reattachment Center
The Limb Reattachment Center is a place mentioned by Four in Fortunate Ben when asked where X was by Book. It seems to be a place where one would go to reattach limbs they lost. X presumably went there because Four dismembered him after he stole Four's line of "Hi Pie, Bye Liy!"

The Massive Department Store
Main Article: The Massive Department Store

The Massive Department Store is an unexplored location, mentioned by Foldy to which Yellow Face promotes items for. It is known to sell products such as Bubble Transformers, Box of Paper Slips, Revolutionary Headphones, and various other products.