Santa Maria de la Sede in Seville!
This is the world's largest Gothic Church and the third largest church in Europe (after St. Peter's in Rome and St. Paul's in London). When they ripped down a mosque of brick on this site in1401, the Reconquista Christians bragged, "We'll build a cathedral so huge they will take us for madmen", so they built for 120 years!!
The high altar piece is 65 feet tall and has 44 scenes from the life of Jesus.
Unfortunately it was going through some restoration so we could not see it. This photo is of a side altar.