XVth C. Flemish Tapestry "L'Arithmétique" from the Musée de Cluny on the Left Bank. Depicts the displacement of the abacus by Hindu-Arabic numerals.

Old print of the Place Royale (called Place des Vôsges since the Revolution), from the time of Mersenne and Descartes. This area was only a few steps from Mersenne's rooms at the Minimes convent.

The oldest mechanical clock in Paris (actually, a XIXth C. reproduction of a XIVth C. original.) The tower is on the Concergerie on the Ile de la Cite. It is said that its striking the hour of 2:00 AM on the morning of Aug 23, 1572 gave the signal for the beginning of the St. Bartholomew's day massacre.

Interior of the church Saint-Etienne-du-Mont, burial place of Blaise Pascal.