I visited the Pantheon, the tomb of Napolean. It's big and statesman-like. A huge dome caps the structure and it's laid out in a cross. Apparently during the construction, in between one of the many French Republics, they were going to turn it into a church. The French built a huge crypt below that you tourists can visit. The crypt was designed to house many dead bodies and being entombed at the Pantheon is a very high honour as only those who have contributed significantly to the liberty of la France receive that honour.
There are at least four physicists there: Perrin, Langevin and the two Curies. There's a Sadi Carnot, but not the Sadi Carnot of the thermodynamic cycle. Some big dude general I think.
Foucault's Foucault's pendulum is there. Foucault's pendulum is basically a very long pendulum. So long that the rotation of the earth causes the swinging of the pendulum to do tiny figure of eights. Apparently when Foucault first dreamed up the experiment, the highest structure Foucault could find was under the dome of the Pantheon.
Inside the crypt, Voltaire and Rouseau are buried facing each other. Apparently they detested each other in life. They have been forced to face each other in death. Although Voltaire got a funky sculpture in front of his tomb.