First off, Zaragoza is a gem. it is a most beautiful, relaxed and lovely city to visit. On the mainline between Madrid and Barcelona, 90 mins each way, it's alos ideally located for a few quieter days.
The Basilica is its centrepiece, right on the banks of the Ebro, and it is very spectacular. It's high Bqroque so do expect highly ornate decoration, evocative lighting, lots of gilt and expansive space.
There are two Goya Frescoes on the ceiling - he was local and because the Archbishop was not sufficiently in awe of his work, he left and never returned.
And look out for the two holes in the ceiling made by bombs from an air raid during the civil war, neither of which exploded. A miracle they say.
I can't find a Trip Advisor entry for a wonderful restaurant nearby, El Ciclon, in the arcade across the square, so a little entry here will have to do. Go to El Ciclon, its fun, lovely food, great service, reasonable rates and very welcoming.