Pennsylvania Avenue lighthearted celebrations, including a series of day- and nighttime Shriner's parades in the 1920s and 1930s. Thomas and Concepcion Picciotto are the founders of the White House Peace Vigil, the longest running anti-nuclear peace vigil in the US, at Lafayette Square on the 1600 block of Pennsylvania Avenue. After the Oklahoma City bombing in 1995, the Secret Service closed the portion of Pennsylvania Avenue in front of the White House to all vehicular traffic. Pedestrian and bicycle traffic, however, was still permitted on the sidewalk. After 9/11 this policy was made permanent. Near the White House traffic is redirected to
Pennsylvania Avenue earliest streets constructed in the Federal City. The first reference to the street as "Pennsylvania Avenue" comes in a 1791 letter from Thomas Jefferson. One theory is that the street was named for Pennsylvania as consolation for moving the capital from Philadelphia. Both Jefferson and George Washington considered the avenue an important feature of the new capital. After inspecting L'Enfant's plan, President Washington referred to the thoroughfare as a "Grand Avenue". Jefferson concurred, and while the "grand avenue" was little more than a wide dirt road ridiculed as "The Great Serbonian Bog", he planted it with rows of fast-growing Lombardy