My guidebook: Westminster Cathedral
Westminster Cathedral is not Westminster Abbey.
(Just like, technically, Westminster Abbey is not an abbey, partially thanks to Henry VIII and his self-explorations.)
Westminster Cathedral is the main Catholic Church of England and Wales. From the outside, it’s Hampton Court that was dropped in Hagia Sophia and rolled its way through Alhambra — all this at the turn of the 20th century with no intention to finish. An interesting building with a selection of mosaics made over decades, including a very British rendition of — so close to my Eastern heart — Byzantine golden tones and abstract florals.