The Uppsala Cathedral was mind-blowing. It was seriously awesome inside and out.
We first walked up the main aisle, looking at the huge arches and painted surfaces. Since there really wasn't much in terms of signage or any free pamphlets, we purchased little a book. It didn't go into any detail for half of the chapels, but it minimally highlighted a few really interesting bits.
Most interesting, perhaps, is the front-most chapel beyond the altar. Originally a chapel dedicated to Mary (with the blue and the stars covering the entire vault), it became the final resting place for Gustav Vasa, Sweden's first hereditary king.
Also and we really didn't know until we got the book, albeit, we knew it was important (even if it was the least lit), the one side chapel housed both the reliquaries of both St. Erik and St. Birgitta. Relics of saints (including a very important one) in an old Protestant Cathedral. Well, they've been sleeping there for years... it's ok.
Linnaeus' grave is in the church as well, and was festooned with herbs and botanicals. Even though the book didn't list it, one of the side chapels houses the ostiary of Emanuel Swedenborg. I can write more, but it was just really cool - look at the pictures.