Most memorable site in Paris.
I've been to the Louvre, the Eiffel Tower, Notre Dame, and many other places in Paris, but the place I always remember and return to on every visit is Ste Chapelle. When you enter the lower chapel you may think the church dull, as there is little glory other than the ceiling vault painted with stars. However, once you ascend to the upper chapel, you will enter perhaps the most beautiful church you have ever seen. This is Gothic architecture at its best. It seems that there is nothing but glass holding up the roof. You are surrounded by red and blue light streaming in from every direction. "Read" the windows from your lower left to your upper right . They will take you from Creation to Apocalypse. Make sure to go out on the balcony.
Ste Chapelle was created by the King of France Louise IX (Saint Louis, or if you are from my corner of America, San Luis Rey).
Public concerts often occur in the Upper Chapel.