Panthéon and Conciergerie

The Pantheon and the Conciergerie tell two halves of the French story, one of glory and one of terror, within a short walk of each other on the Left Bank and the Ile de la Cite. The Pantheon crowns the hill of the Latin Quarter, a vast neoclassical temple begun as a church to Saint Genevieve and reborn during the Revolution as a secular mausoleum for the nation's heroes. Its motto reads to great men, the grateful homeland. Beneath the soaring dome rests a crypt holding Voltaire, Rousseau, Victor Hugo, Emile Zola, Marie Curie, Louis Braille and other figures who shaped France and the world.

Inside, the building is a marvel in its own right. The nave displays a working copy of Foucault's Pendulum, the famous experiment that first demonstrated the rotation of the earth in 1851, swinging silently under the dome. In the warmer months you can climb to the colonnade just below the dome for one of the finest open air panoramas in Paris, with Sainte-Chapelle, the Eiffel Tower and the rooftops of the Latin Quarter laid out around you.

The Conciergerie, by contrast, is a place of shadows. Once part of the medieval royal palace, it became the principal prison of the Revolution, where more than 2,700 people, Marie Antoinette among them, were held before the guillotine. You can see the magnificent vaulted Hall of the Men at Arms, one of the largest surviving medieval halls in Europe, and a reconstruction of the queen's cell.

Both sites use timed entry, so book skip the line tickets online, and consider a combined Conciergerie and Sainte-Chapelle ticket since they share an address. Visit the Pantheon in late morning for the pendulum and the climb, then walk down to the island. To get there take Metro line 10 to Cardinal Lemoine or the RER B to Luxembourg for the Pantheon, and line 4 to Cite for the Conciergerie.