Circumnavigation is the complete navigation around an entire island, continent, or astronomical body (e.g. a planet or moon). This article focuses on the circumnavigation of Earth. The first recorded circumnavigation of the Earth was the Magellan–Elcano expedition, which sailed from Sanlucar de Barrameda, Spain in 1519 and returned in 1522, after crossing the Atlantic, Pacific, and Indian oceans. Since the rise of commercial aviation in the late 20th century, circumnavigating Earth is straightforward, usually taking days instead of years. Today, the challenge of circumnavigating Earth has shifted towards human and technological endurance, speed, and less conventional methods. Etymology The word circumnavigation is a noun formed from the verb circumnavigate, from the past participle of the Latin verb circumnavigare, from circum "around" + navigare "to sail" (see further Navigation § Etymology). Definition A person walking completely around either pole will cross all meridians, but this is not generally considered a "circumnavigation". The path of a true (global) circumnavigation forms a continuous loop on the surface of Earth separating two regions of comparable area. A basic definition of a global circumnavigation would be a route which covers roughly a great circle, and in particular one which passes through at least one pair of points antipodal to each other. In practice, people use different definitions of world circumnavigation to accommodate practical constraints, depending on the method of travel. Since the planet is quasispheroidal, a trip from one Pole to the other, and back again on the other side, would technically be a circumnavigation. There are practical difficulties (namely, the Arctic ice pack and the Antarctic ice sheet) in such a voyage, although it was successfully undertaken in the early 1980s by Ranulph Fiennes. History The first single voyage of global circumnavigation was that of the ship between 1519 and 1522, now known as the Magellan–Elcano expedition. It was a Castilian (Spanish) voyage of discovery. The voyage started in Seville, crossed the Atlantic Ocean, andafter several stopsrounded the southern tip of South America, where the expedition named the Strait of Magellan. It then continued across the Pacific, discovering a number of islands on its way (including Guam), before arriving in the Philippines. The voyage was initially led by the Portuguese Ferdinand Magellan but he was killed on Mactan in the Philippines in 1521. The remaining sailors decided to circumnavigate the world instead of making the return voyageno passage east across the Pacific would be