Short answers, pulled from the story.
The year 1933 marked the birth of a massive space inside Rockefeller Center. This room rose three stories high to accommodate full orchestras and stood as the largest radio studio in the world at that moment.
Arturo Toscanini led his NBC Symphony Orchestra within these walls starting in 1937. A young Samuel Barber heard his Adagio for Strings performed from this exact spot for the first time ever during this period.
Engineers transformed the facility for television production in 1950. Kraft Television Theatre became the primary program airing from the converted set after cameras replaced microphones as the main tool for capturing live events.
A price tag of $250,000 covered the revamp before SNL premiered in January 1975. Lorne Michaels oversaw changes to make the space suitable for sketch comedy and the show has broadcast live from here continuously since that initial season.
MSNBC's Morning Joe held its tenth anniversary celebration before a live crowd on the 19th of September 2017. This event took place inside the studio which also hosted other shows like Today and Late Night with Conan O'Brien.