I stopped at Zaragoza years ago when I accompanied my grandmother on a coach tour pilgrimage to Lourdes made up of members of her local congregation (a Catholic Church in Alicante).

Being the kind of trip it was, all I remember about Zaragoza was the visit to the Virgin of the Pillar and the Basilica in which it is housed.
I don’t think it is possible to exaggerate what the symbolism of the building and its contents means for religious Spaniards and the small area where the pillar can be touched is worn away by centuries of veneration (seeing this indentation up close and how people interacted with it affected me quite a bit). I honestly don’t know what someone with no cultural connection to the Virgin of the Pillar would make of the Basilica. However, it is an impressive example of the baroque style and there is a “torre mirador” which lets you see the distinctive roof and towers of the Basilica up close as well as the neighbouring city.