With tools like GPS, satellite imagery, and aerial photography, modern mapmakers are able to "get off the ground" and observe the planet from a distance, making their maps extremely accurate. However, it wasn't always this way. Creating a picture of the Earth was much more difficult for early cartographers, who were limited not only by their perspective but also by how much of the world had been discovered and recorded in their time.

The first geographers relied on a lot of guesswork and rumors to build their picture of the world. Still, they were able to create amazingly accurate maps, considering the tools of the time. As you click through this slideshow, try to imagine how each cartographer went about the business of creating maps.

Eratosthenes, who invented the science of geography, made one of the first maps of the world in about 194 BCE. As you can see, it's mostly accurate around the Mediterranean Sea where he lived, but gets less precise toward the edges.

In 1154 CE, Arab geographer Muhammad al-Idrisi drew a map of the world, called the Tabula Rogeriana. Notice that al-Idrisi's map seems "upside down," with South facing up, not down as in modern maps. This atlas would be in use for the next 300 years.

Gervase of Ebstorf made this giant map out of thirty stitched-together goatskins around 1235 CE. It has East pointing up, and shows how geographers at the time valued shape and symmetry over accuracy when making their maps of the world.

This modern atlas shows how far we've come in our understanding of the features of the globe.