Today we've been on a tour of the BBC studios in "The Mailbox" building in Birmingham, to see behind the scenes of the BBC radio and television.
We were shown round the recording studios of the programme "The Archers", which is the oldest soap opera in the world, since it started in 1951 and has run continuously ever since.
The studio is full of artefacts used for different sound effects on the programme. When they want to record someone going up or down some steps or stairs they use this flight; each step has three different surfaces to get just the right sound.
(English readers will probably understand what I'm saying; others may be completely puzzled!)