When I visited in 2002 there was a wedding in progress. The choir's voices were surreal. A visit during a mass would be worthwhile for the opportunity to hear the incredible acoustics of the cathedral. The sound was unforgettable as was the monestery. It is well worth the visit especially for anyone wishing to learn more about Portugal's history and architecture. The unfinished chapel/tomb is the last stop on the tour and well worth the effort. It's beautiful.