Founded as an Augustinian priory in 1122, Carlisle Cathedral is one of England's smallest cathedrals, but that compact scale makes it more intimate than many of its grander counterparts. The choir ceiling, painted in the 15th century with stars and suns against a brilliant blue ground, is stunning — and almost entirely overlooked by the tourists filing through the castle a few hundred metres away.
The east window contains some of the finest medieval stained glass in the north of England, dating from around 1380. Free to enter, though donations are welcome.