The Plus Fours Routefinder

Before Global Positioning Systems (GPS), people had to navigate using devices like the Plus Fours Routefinder, shown below. It’s from 1920 and consisted of a collection of small scrolling maps that you’d “load” into the watch-like device before your trip. As you progressed along your route, you’d scroll the map forward to reveal your next turn, mileage, and where to stop.


Found at Crunch Gear