Europe may not be on the edge of economic progress at the moment, but it has a pretty good heritage! And to celebrate it, the Council of Europe and the European Commission have created a yearly event called "the European heritage days"! Principle? Open the doors of historical buildings that are normally closed to the public. Paris (and France in general) has a lot to offer on those days which explains why the streets are packed with people and why I have had trouble making my way through any of the interesting stuff... I did manage to visit the Eglise Saint Joseph des Carmes though, which is rarely open. It's known for its stunning ceiling that you can see in this photo, on the making of.