It's official title is the Basilica of the Sacred Heart of Paris. Most simply refer to it as Sacre-Coeur.
I am not catholic, so I'm unfamiliar with the differences between the various religious buildings (a church, a cathedral, a basilica). And history has never been my favorite subject, so I'm not well-versed in the religious and political circumstances surrounding this 19th century project.
I do know it took nearly two decades to complete: from 1875 to 1914, and the architectural style is completely different from the Medieval Notre Dame cathedral, and the ornate Palais Garnier.
Scare Coeur is built on the highest point of the city, the summit of the butte de Montmartre. It is an effort to reach the top, but once you climb all the stairs (or take the funicular), the views are magnificent.
The white stone against the deep blue sky is absolutely breath-taking. The size, the detail, the beauty... all work together to command reverence. When you step inside, you know you are standing on hollow ground.
I am so enamored with this building that I made it the focal point of my Paris room. I can now sit on my couch, look out the "window" and pretend I live in Montmartre. Je suis tres contente ici...