The center of Monmartre is the beautiful Sacre Coeur basilica. It's a very unusual cathedral, that looks almost Middle Eastern, with tall domed towers and the pure white stone. It always looks to me like it's been plucked out of the desert and put onto a Parisian hillside.
Back behind the cathedral is a beautiful (although closed) vineyard. I did my best to fumble through the placard with information about it, but then I overheard people talking about how the wine is awful, because of the lack of sunlight, but sells for a very high price because they donate the proceeds to charity.
My last stop in Monmartre was to the artist square, where dozens of artists and patrons cram into a small square to paint, sell, and buy art. It's great to see all of the artists out there working in such a picturesque place. It makes you feel like you're sitting in the residual energy of Toulouse-Lautrec, Van Gogh, and all the other artists who worked there, trying to soak up anything they left behind.