I blogged before about how conservation of historical monuments can in itself be a tourist attraction.
The Karlskirche in Vienna is a particularly interesting example. The church is under restoration, partly filled by a skeleton of steel scaffolding reaching up into the dome. A lift takes visitors up to a platform under the dome, for a close up view of Rottmayr's wonderfully dynamic paintings. Then you can - if you're so inclined and have a head for heights - make your way up a rather wobbly staircase into the lantern right at the top.
The entry fee is a steep 6 euros - but for this amazing chance to see the paintings from close up, it's worth it.