The Panthéon is located just a few blocks southeast of the Sorbonne, on the top of a hill. The dome in this picture is the one I could see from my hotel window. The legend above the pillars reads "Aux grands hommes la patrie reconnaissante", which means (roughly) "In recognition of the great men of the country". This neoclassical building was designed by Jacques-Germain Soufflot and built over the period from 1758-1789. It was originally a church dedicated to St. Genevieve, the chief patroness of the city of Paris, but was permanently rededicated as a civic monument when Victor Hugo died.
The interior of the Panthéon. The dome is so architecturally perfect that in 1851 the physicist Léon Foucault used it to test his famous 67 meter pendulum demonstrating the rotation of the earth. You can just barely see a copy of his pendulum hanging from the dome, ending in the middle of the object that looks like a circular tape measure. The artwork behind the pendulum also represents this event, I believe. At the base there is a small group of highly polished precise mirrors. When you look down at them, you see the entire interior of the building reflected. You can see a small group of people looking down at the mirrors.
Another shot of the interior of the Panthéon, showing some of the beautiful floor and paintings honoring St. Genevieve.
An over-the-top statue depicting the National Convention of the French Revolution. The inscription reads "Vivre libre ou mourir" - "Live free or die".
Beneath the Panthéon, in dimly lit halls of finely hewn stone, many of the great men and women of France are buried in crypts, including politicians, writers, scientists, and members of the Resistance. Those honored include Victor Hugo, Pierre and Marie Curie, Jean-Jacques Rousseau, André Malraux, Émile Zola, René Cassin, Jean Monnet, Jean-Paul Marat, Paul Painlevé, Jean Moulin, Alexandre Dumas, Louis Braille, Souflot (the architect of the building), and Lagrange. The people visiting the crypts were very quiet and respectful, a bit in awe I think. Some of them had left little scraps of paper on the crypts with emotional messages. One of them, on Victor Hugo's crypt, was in English, and it simply said "Your writings have meant so much to me. Thank you. Rest in peace." On Lagrange's crypt I saw one with an equation he had discovered, with the single word "merci". I visited all the crypts and paid my respects, then stood at the crypt of Voltaire in this picture and had a personal moment of silence to remember and honor all of them. It was the end of my last day in Paris, and it was a fitting way to end my trip.
I read Voltaire in English translation when I was young, and I was captivated by his wit. There's a story that on his death bed, a priest tried to get him to renounce Satan. He is reported to have said "now, now, my dear man - this is not the time to be making enemies." How funny, and how French, is that?