Circumnavigation – literally, "navigation of a circumference" – refers to travelling all the way around an island, a continent, or the entire planet Earth.

In principle, if a person walks completely around either Pole, they will have crossed all meridians, but this is not generally considered a "circumnavigation." A basic definition of a global circumnavigation would be a route which covers at least a great circle, and in particular one which passes through at least one pair of points antipodal to each other. In practice, different definitions of world circumnavigation are used, in order to accommodate practical constraints depending on the method of travel. Since the planet is a sphere, a trip from one Pole to the other, and back again, would technically be a circumnavigation, but practical difficulties generally preclude such a voyage.

For the wealthy, long voyages around the world, such as was done by Ulysses S. Grant, became possible in the 19th century, and the World Wars moved vast numbers of troops around the planet. However, it was later improvements in technology and rising incomes that made such trips relatively common.

Ferdinand Magellan (Portuguese: Fernão de Magalhães, IPA: [fɨɾˈnɐ̃w ðɨ mɐɣɐˈʎɐ̃jʃ]; Spanish: Fernando de Magallanes, IPA: [ferˈnando ðe maɣaˈʎanes]; c. 1480 – 27 April 1521) was a Portuguese explorer. He was born in Sabrosa, in northern Portugal, and served King Charles I of Spain in search of a westward route to the "Spice Islands" (modern Maluku Islands in Indonesia).

Magellan's expedition of 1519–1522 became the first expedition to sail from the Atlantic Ocean into the Pacific Ocean (then named "peaceful sea" by Magellan; the passage being made via the Strait of Magellan), and the first to cross the Pacific. It also completed the first circumnavigation of the Earth, although Magellan himself did not complete the entire voyage, being killed during the Battle of Mactan in the Philippines. (For background see Exploration of the Pacific).

Magellan also gives his name to the Magellanic Penguin, which he was the first European to note, and the Magellanic clouds, now known to be nearby dwarf galaxies.