Recently we took my parents up to the north of France, mainly to see the World War II D-Day landing beaches (aka Operation Overlord sites) and the World War I cemeteries. A good place to base oneself for visiting these places is the city of Amiens in Picardy, and indeed Amiens is well worth visiting just for its own sake. It has a magnificent cathedral for one thing - the biggest and tallest in France, and deservedly a World Heritage Site.
Amiens Cathedral is big. Really big. And packed with so much detail you don't know where to look next in order to take it all in and not miss any of the characterful carving (in stone on the front, in wood in the choir) or the outrageous Baroque confections that make up the high altar, the pulpit and some of the tombs. The detail is from every century since the Cathedral was begun in 1220 and the quality is superb. So is the space - the place is huge, swallowing all this detail and still being awe-inspiring the way a Cathedral should be.
Look at the great airy spire, with its attenuated angels keeping watch. This is the real thing (unlike Notre Dame de Paris, whose similar looking spire is a 19th century addition). In French this style of lead covered timber spire is called a fleche (ie arrow).
Look at this demonstration that more is more. (You can go round the back of this distinctly OTT but undeniably skillful arrangement and find that the artisans had thought of that too - the back is painted more simply, but maintains the trompe l'oeil.)
Look at the affecting scene being played out on the end of one of the choir stalls. For the type of single, relatively brief visit the average tourist is likely to make the choir is, in my opinion, the single best part of Amiens Cathedral and the 16th century choir carvings alone makes it worth a visit. You can get right up close to little vignettes like this one we photographed. At this level, the carvings are unpainted, but higher up, in the choir screen, they are polychrome masterpieces, even more detailed than the stalls.