Earth's gravity is the most overriding force in human history. It keeps us in our beds at night, pulls us back to the ground after every stride on a long run, stands up our homes and skyscrapers, and fixes the Moon in the sky. And yet, precisely measuring Earth's gravity is surprisingly difficult.
Detailed maps of that pull offer significant clues to what lies under Earth's surface, not to mention critical information for architects and engineers. Here are the highest-resolution maps of the planet's gravity ever made.