I liked this gargoyle on the façade of Sacre Coeur because you can see really clearly how it is actually a rainwater runoff spout.
Views from the top:
The photography policy in the cathedral is oddly unclear, so I only got a few photos before I got shouted at, along with a bunch of other people. Frankly, the minder shouting at people seemed more disruptive than people taking photos.
The lower register of the lefthand part of the apse dome mosaic, which shows churchmen proselytizing to a variety of native peoples in the New World. Because of the minding and the shouting I didn't get a chance to take better pictures of it, but I'd be interested to find out more about it.