premise: To celebrate Bastille Day (14 July) or the 1944 Liberation (25August), blue, white, and red laser beams are bounced off the Eiffel Tower, Arc de Triomphe, and H??tel de Ville.
hypothesis: Moments of silence and an eerie atmosphere accompany the darkening of all lights on the Eiffel Tower, Arc de Triomphe, and Hotel de Ville during the commemoration ceremonies of Bastille Day and 1944 Liberation Day.