Sesame Studio

Sesame Studio is the name of an theater that currently houses Elmo's World Live:

 Image from IGOUGO

When the park opened in 1980, Sesame Studio was a very different attraction. One of the popular features was the Ernie's bathtub photo op:

1985 Image from YouTube

Children could step into a bathtub with Ernie and his rubber duckie:

1988 Image from YouTube

The bathtub was located next to a large, indoor, replica of The Sesame Street Set. 

 1988 Image from YouTube

This replica was phased out after the introduction of the larger outdoor neighborhood in 1988:

2012 Image

The Sesame Street Set was located next to a small chroma key theater:

 1985 Image from YouTube

The Sesame Street Set featured Big Bird and Little Bird peeking out of the nest and Prairie Dawn, Grover and Count Von Count looking out the windows.

1985 Images from YouTube

Kids could also pose for pictures inside Oscar's trash can (which was actually a half trash can open in the back.)

 Image from ThirteenLove

There was also a second floor balcony (which included a walkway to the upstairs exit of the studio.)

1985 Images from YouTube 

The chroma key stage would show children how the special effects were done on their favorite TV shows.

1985 Images from YouTube

The studio was transformed in the 1990s to create the larger theater that currently shows Elmo's world. For a time, the larger theater existed alongside exhibits like a room of mirrors (called Teleidoscope Temple) and these play puppets:

1999 Image

I'm not sure what the space is used for today, but it seems like the current theater only occupies two thirds of the building.


2015 UPDATE:
When working on the Sesame Place book I found that some of the science elements were also located on the second floor of the Computer Gallery.

Episode 16 of The Purple Stuff Podcast features a story about Return of the Jedi special effects being shown in the blue screen theater,