From Muppet Wiki

Buckingham Palace, located in London, England, is the royal dwelling place for the Queen of England and her family.

• In Episode 308 of Fraggle Rock, Uncle Traveling Matt pays a visit to the palace. He comes to the conclusion that the hats worn by the Silly Creatures (palace guards) are actually pets, and the owners are very careful not to wake them. According to Uncle Matt, this is why they never speak.

• Kermit the Frog performed at Buckingham Palace for the Queen's Jubilee in 2002.