You won’t find Harry Beck’s face on any coins or postage stamps, but his fingerprints are all over London. Born in 1902, Beck was an English engineering draftsman who sparked a small revolution in the early 1930s when he created a radical new map of the London Underground.

His linear, color-coded diagram was at first greeted with apprehension from transit authorities, but soon proved popular among London commuters. Today, it’s arguably the most recognizable and influential transit map in the world, having spawned similar designs in major cities across the globe.

Photo Credit: The original Tub map designed by Beck. Wikimedia Commons