Soufflot's neo classical megastructure was the architectural grand projet of its day, commissioned by a grateful Louis XV to thank Sainte Genevieve for his recovery from illness. The austere barrel-vaulted crypt now houses Voltaire, Rousseau, Hugo and Zola. Pierre and Marie Curie's remains were transfered here in 1995; Alexandre Dumas in 2002. It is open from 10 am to 6 pm daily. You have superb view from the dome.