A globe is a three-dimensional scale model of the Earth or other round body. Because it is spherical, or ball-shaped, it can represent surface features, directions, and distances more accurately than a flat map. On the other hand, a globe may be less practical for travelers, since globes are much bulkier than flat maps and often carry less detailed information.

The oldest known globe was made more than 2,100 years ago by Crates of Mallus, a Greek philosopher and geographer who lived in what is today Turkey. The oldest globe that survives to this day was made by the German geographer Martin Behaim in 1492—just before Christopher Columbus sailed to the New World. This globe is more accurate than Crates', but still leaves out North America, South America, Australia, and Antarctica.

The Earth is not the only planet that has been mapped onto a globe. In the past few decades, spacecraft have made detailed maps of the surfaces of other planets and moons. Globes for some of them, such as the planet Mars and our own Moon, are available for purchase.

Even the night sky around the Earth, known as the celestial sphere, has been mapped onto a globe. Celestial globes represent stars and planets visible above certain parts of the Earth. Many constellations, such as the Big Dipper, are outlined into familiar shapes on celestial globes. Looking for patterns on celestial globes makes finding individual stars easier to spot.

Like most early terrestrial globes, most early celestial globes were made of metal. Metal globes are usually cast in two halves, or hemispheres. These halves are then welded together with hot metal, creating a seam, or raised line, in the middle of the sphere. It is nearly impossible to create seamless globes—globes that are made of a single piece of metal. Nevertheless, astronomers and metalsmiths in what is today India and Pakistan created such celestial globes in the 1500s.

An ancient type of globe is the armillary sphere. An armillary sphere has a mini-globe of Earth surrounded by rings representing movement of visible stars and planets. The rings are adjustable, so they reflect the stars and planets visible at different times of the year in different places on the globe. Before the invention of the telescope, armillary spheres were the most important tools astronomers had. In fact, celestial globes and armillary spheres have likely been used at least as long as terrestrial globes, if not longer.