In the mid-1850s, before the Florida Reef was fully marked by lighthouses, the US Coast Survey installed a series of 15 unlit, iron posts to warn mariners that they were approaching the shallows of the reef. The markers ran the length of the reef from Key West to Key Biscayne and stood over 30 feet out of the water, each one bearing a large iron letter as an indicator their location. They were known as “Totten Beacons,” named after Lt. James Totten who supervised their installation.

In 2014, archaeologists from the Mel Fisher Maritime Museum and Florida Keys National Marine Sanctuary partnered to document the surviving remains of these early Florida Keys aids to navigation. Three-dimensional photogrammetry was a key part of the project.