The United States has 4.1 million miles of roads, more than any other nation in the world. About 47,000 of those miles are part of the Interstate Highway System, established by President Dwight Eisenhower in the 1950s. The country also has 127,000 miles of railroad tracks and about 25,000 miles of navigable rivers and canals (not including the Great Lakes). The imprint of that transportation web becomes easier to see at night. The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite acquired this natural-light, mosaic view of the continental United States. The VIIRS instrument uses a "day-night band" of wavelengths that is sensitive to low light levels and manmade light sources. The images were collected just three days before the new moon, so reflected light from space and the atmosphere was relatively low. It was also a rare night when most of the nation was cloud-free.