As twilight turns to night, the city of Paris lights up. Streets and buildings are bathed in light, alongside grand monuments such as the Hôtel National des Invalides, whose famous dome shines out in our homepage image. It was built during the 17th century under Louis XIV, as a hospital and home for army veterans. It was also Louis XIV, known as the Sun King, who ordered streetlights to be erected throughout the city to light up dark alleys where lawbreakers might lurk. Parisians were also asked to put up lanterns and oil lamps, and place lit candles in their windows.