What is the Carbuncle Cup given out to annually?

It's a slightly jokey architecture award given to the ugliest building built in the UK. Its name comes from (then) Prince Charles's intervention in the 1980s to work being done done on an extension to the National Gallery, in Trafalgar Square, where he likened it to a "monstrous carbuncle on the face of a much-loved and elegant friend".

https://en.wikipedia.org/wiki/Carbuncle_Cup#:~:text=The%20Carbuncle%20Cup%20is%20an,in%20the%20last%2012%20months%22.