La Catedral de Santa Maria la Real Almudena is an impressive structure. This cathedral is massive and is the seat of the Archdiocese of Madrid.
Construction of the cathedral began in 1883, however the cathedral wasn’t completed until 1993. It was consecrated by Pope John Paul II, and remains the only Spanish cathedral ever consecrated by a Pope.
The cathedral grounds have an area dedicated to Pope John Paul II as well.
The cathedral contains beautiful stained glass throughout.
It is definitely worth a visit when in Madrid.