The Caribbean Sea is sometimes described as an American Mediterranean, but this is to ignore the fact that the Caribbean is actually a reverse image of the Mediterranean Sea, at least in geographical terms. On the other hand, both seas, until the Suez and Panama canals were constructed, could only be entered from the Atlantic, though whereas the Mediterranean has only one entrance, at the Strait of Gibraltar, the Caribbean has multiple entrances between a whole string of islands. It therefore hardly helps to describe the Caribbean in Mediterranean terms, though they were both, in a curious element of similarity, the recipients of waters from a giant river, the Mississippi (plus the Rio Grande and the Orinoco) and the Nile, plus the Black Sea rivers.

The two great continents of North and South America are linked by the narrow Isthmus of Panama, which encloses the Caribbean at its western end. At the eastern end of the sea there is a string of relatively small islands, the Lesser Antilles and the Bahama Islands, between which there are numerous passages, though not all were favoured by sailors. The distance between the two extremes is perhaps 3000 kilometres. The sea itself is divided into two parts by the long narrow island of Cuba and the other large islands of the Greater Antilles. The north part is the Gulf of Mexico, and the south is the Caribbean Sea proper.

This geographical layout is the clue to understanding many of the peculi¬arities and particularities of Caribbean maritime history. The openings on the east, through the many islands, scattered between Guiana and Florida, allow a strong current to flow from east to west out of the Atlantic and into the Caribbean; the solid barrier of the Isthmus and Central America forces the current to turn north and flow out of the Caribbean between Cuba and Yucatán; the closed nature of the Gulf of Mexico diverts the current once more past the north coast of Cuba, flowing this time west to east, and it exits the sea between Hispaniola and Florida and swings north to flow between the Bahama Islands and Florida; at this point it becomes the Gulf Stream, to which most Western Europeans are extremely grateful for their equable climate.