There's a map on the bottom of the Mariana Trench - Apparently.
The Bathymetric Map of the Mariana Trench, created by the National Oceanic and Atmospheric Administration (NOAA) in 2009, is etched into a bronze plaque at the bottom of the trench. The map, measuring 1.6 square meters, provides a detailed topological representation of the trench's seafloor. The plaque is secured to the seafloor using a titanium framework, making it the lowest-lying map in the world.