The iconic building from which the BBC began radio broadcasting in 1932 and from where all TV and radio broadcasting in London has taken place. Since 2013 it no longer offers tours to the public, but you can have a look at the restored art-deco foyer and peer down into the newsroom through floor-to-ceiling windows by visiting the shop that sells BBC-branded gifts and souvenirs.
Don't miss the Dalek near the entrance. The public can still attend recordings of the Radio Theatre as members of the audience but this requires advance booking; see the website for details.