The great world fairs of the nineteenth century served as experimental zones for modern illumination of architecture. At the 1889 fair in Paris, for example, the newly erected Eiffel Tower was transformed into a lighthouse at night. However, it was only in the 1920s that a building's evening façade became a central issue for architects, who sought avant-garde, technical, and aesthetic ways to light up the metropolises of the world. Both European and American architects wanted to create a separation between their work and the electric signs that dominated cities, so they illuminated their skyscrapers with colored floodlights in an attempt to stand out against garish neon signs. Contemporary architects use many of the historical concepts of illumination, and due to technological advances, they are able to implement them in particularly dramatic ways.This publication commences a dialogue among historical buildings and utopias, more recent designs, and paintings and photographs that feature nighttime façades. Scholarly texts shed light on this extraordinarily exciting chapter of architectural history.