The Silver Bow airway beacon, built in 1937, guided pilots along the Northern Transcontinental Airway’s east-west airmail route between New York City and Seattle. The beacon was part of the Three Forks to Gold Creek “cutoff” route, a string of five beacons between Butte and Helena that connected pilots to the north-south National Parks Airway route. The fifty-five-foot-tall, steel structure held a revolving, one-million-candle-power beacon originally encased in a glass dome. Red and green directional lights on the tower indicated the route, while flashing red course lights identified the beacon in Morse code. Gas-powered generators housed in a nearby shed powered the beacon until the early 1940s when it was connected to electrical lines. A warming house stood nearby, offering shelter for the mechanics who serviced the beacon every two weeks, often in harsh weather. Before the advent of radio navigation, airway beacons served as a critical nighttime navigational aid, guiding pilots along routes between airports. From 1926 to 1938, the U.S. Bureau of Air Commerce created 18,000 miles of airway corridors and installed 1,550 airway beacons to mark the routes for night flying. In Montana, the International Derrick and Equipment Company of Columbus, Ohio, fabricated the towers, which were paid for with funds from the Works Projects Administration. Though most of the country’s beacons were replaced with ground-based radio stations by the mid-1970s, Montana’s private pilots successfully lobbied to keep seventeen beacons lit through 2017. As of 2021, several adopted beacons still light the night sky, recalling Montana’s aviation heritage.