At first , Lauren and I wanted to visit the Catacombs and the Musée d'Egouts, but both of them were closed for renovations. Later, we visited the Panthéon, which is known for housing the graves of famous French people such as Voltaire, Zola, and the Curies.
There's also a pendulum hainging from the ceiling to recreate Foucault's experiment from 1851, when he used the pendulum to prove the Earth's rotation. We're not sure why there's a cat statue next to it, but it was cool to see the place where such an important experiment had happened. (-Lisa and Lauren)