Answer: Pilots

Throughout South-Western states like New Mexico, you’ll find a curious relic from the past. Between major cities in the region, out in the expanse of scrub grass, there are massive 70-foot long concrete arrows embedded in the ground. If you find one of the better preserved installations, you’ll even find a small cabin like structure and a steel tower beside the concrete.

These concrete arrows and companion structures are the vestiges of a long abandoned air-mail system that spanned the United States from coast to coast. Before the days of radar, before the days of GPS tracking and on-board navigation, these huge arrows were used to help pilots flying the most heavily trafficked air-mail delivery routes deliver their payloads. The arrows were originally painted bright yellow and each one was paired with a gas-powered light tower to illuminate the location at night and in inclement weather. The machinery that powered the light tower was kept in a generator hut near the tower’s base and their keepers lived in a nearby cabin.

Although the arrows originally stretched across the country, it is rare to find them east of the Rocky Mountains these days as urban development, harsher winters, and more prolific plant growth have uprooted or obscured the air-mail relics.