This Date in History
July 21, 1910: In the evening, thousands of people on Pennsylvania avenue unexpectedly witnessed the lighting of the tower at the Post Office building. They were left to wonder about the purpose of the illumination. One observer speculated it was a lighthouse for airplanes. The truth of the matter was that the big arc light was put in merely for the purpose of illumination and to make the high tower beautiful with its glimmering incandescents.