A painting inside an old emergency call box in the Kalorama neighborhood. The call boxes were the 18th century's version of a 911 emergency system:

The boxes, typically cast-iron, approximately 4-foot-tall structures topped by a gas burner, were used by citizens and law-enforcement officials to report fires and crimes; upon activation, the boxes would transmit an alarm to the appropriate emergency office and flash a red signal-light. In the 1920s, the gas lamps were removed from many call-boxes and the alarms became electrically powered. With the advent of the 911 system 50 years later, the boxes became obsolete, and many were destroyed. But in Washington, D.C.—where, in 1926, the amount of functional boxes reached an all-time high of 12,371—hundreds remained standing, and preservationists became interested in the future of the sculptural structures. Now, a D.C. neighborhood group is campaigning to transform the unused, weather-beaten boxes into art-installation pieces.

If you click on the little thumbnail above right you should be able to read the text explaining the meaning of the painting in this particular call box. I thought it was interesting because it points out where Justice Sandra Day O'Connor lived in the neighborhood at some point.