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"Round the world" redirects here. For the airline ticket, see Round-the-world ticket.
To Circumnavigate a place, such as an island, a continent, or the Earth, is to travel all the way around it by boat or ship. More recently, the term has also been used to cover aerial round-the-world flights.
[edit] World circumnavigation
A basic definition of a world 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.[1] In practice, different definitions of world circumnavigation are used, in order to accommodate practical constraints depending on the method of circumnavigation. [edit] NauticalThe map on the right shows, in red, a typical sailing circumnavigation of the world by the trade winds and the Suez and Panama canals; overlaid in yellow are the points antipodal to all points on the route. It can be seen that the route roughly approximates a great circle, and passes through two pairs of antipodal points. This is a route followed by many cruising sailors; the use of the trade winds makes it a relatively easy sail, although it passes through a number of zones of calms or light winds. 
In yacht racing, a round-the-world route approximating a great circle would be quite impractical, particularly in a non-stop race where use of the Panama and Suez Canals would be impossible. Yacht racing therefore defines a world circumnavigation to be a passage of at least 21,600 nautical miles (40,000 km) in length which crosses the equator, crosses every meridian and finishes in the same port as it starts.[2] The map on the left shows the route of the Vendée Globe round-the-world race in red; overlaid in yellow are the points antipodal to all points on the route. It can be seen that the route does not pass through any pairs of antipodal points. Since the winds in the lower latitudes predominantly blow west-to-east it can be seen that there is an easier route (west-to-east) and a harder route (east-to-west) when circumnavigating by sail; this difficulty is magnified for square-rig vessels. Since the advent of world cruises in 1922, by Cunard's Lanconia, thousands of people have completed circumnavigations of the globe at a more leisurely pace. Typically, these voyages begin in New York City or Southampton, and proceed westward. Routes vary, either travelling through the Caribbean and then into the Pacific Ocean via the Panama Canal, or around Cape Horn. From there ships usually make their way to Hawaii, the islands of the South Pacific, Australia, New Zealand, then northward to Hong Kong, South East Asia, and India. At that point, again, routes may vary: one way is through the Suez Canal and into the Mediterranean; the other is around Cape of Good Hope and then up the west coast of Africa. These cruises end in the port where they began. [edit] AviationAviation records take account of the wind circulation patterns of the world; in particular the jet streams, which circulate in the northern and southern hemispheres without crossing the equator. There is therefore no requirement to cross the equator, or to pass through two antipodal points, in the course of setting a round-the-world aviation record. Thus, for example, Steve Fossett's global circumnavigation by balloon was entirely contained within the southern hemisphere. For powered aviation, the course of a round-the-world record must start and finish at the same point and cross all meridians; the course must be at least 36,787.559 kilometres (22,858.729 mi) long (which is the length of the Tropic of Cancer). The course must include set control points at latitudes outside the Arctic and Antarctic circles.[3] In ballooning, which is totally at the mercy of the winds, the requirements are even more relaxed. The course must cross all meridians, and must include a set of checkpoints which are all outside of two circles, chosen by the pilot, having radii of 3,335.85 kilometres (2,072.80 mi) and enclosing the poles (though not necessarily centred on them).[4] [edit] Human-poweredThough no one has completed a true circumnavigation solely by human power there have been notable attempts. Guidelines issued by Guinness World Records in December 2006 state that a human powered circumnavigation must travel a minimum of 36,787.559 km (the distance of the Tropic of Cancer), cross the Equator, and each leg must commence at the exact point where the last finished off. There are no requirements to reach antipodal points. To date no one has completed a human-powered circumnavigation according to the guidelines set by Guinness.[5] However people have both bicycled and run around the world[6]. But the oceans have had to be covered by air travel, making the distance shorter than the Guinness guidelines. [edit] Notable circumnavigations[edit] Maritime
It has also been claimed that the Chinese explorer Zheng He completed a circumnavigation on either of his two last expeditions. Although he undoubtedly commanded a fleet much larger in size and number than any contemporary European one, and he performed extensive travels, for long unknown by the western world, there is no evidence that he ever traveled west beyond Africa. Most scholars regard speculations of a circumnavigation as "deeply flawed and dubious".[7] [edit] Aviation
[edit] Mixed travel
[edit] See also[edit] References
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