The Bermuda Triangle is a patch of the Atlantic Ocean, out at sea. It is roughly the sea between Florida, Bermuda and Puerto Rico. Its edges are loosely defined. Writers draw it a little differently. The area people call the Bermuda Triangle covers about 500,000 square miles of ocean. Many ships and planes travel through it. So it is a busy part of the ocean. Why is a busy sea so well known? Part of the answer is its name. Let us look.

The name Bermuda Triangle comes from a 1964 magazine article by a writer named Vincent Gaddis. For many years, people have told stories and written books about it. A 1974 book by Charles Berlitz became a best seller. It made the Bermuda Triangle famous. In the 1970s a librarian named Larry Kusche checked the original records behind the stories instead of just retelling them. He found that ships said to be lost in calm weather had actually met storms. Some incidents happened far outside the Bermuda Triangle. Some did not happen at all.

Others have looked at the same question. NOAA, the U.S. ocean science agency, says there is no evidence that unexplained trouble happens more often in the Bermuda Triangle than in other busy parts of the ocean. The U.S. Coast Guard does not treat it as an area of special danger to ships or planes. Lloyd's of London is the ship insurance company. It is reported not to see the Bermuda Triangle as an especially dangerous place. A 2013 WWF study of the most accident-prone waters for shipping did not list the Bermuda Triangle.

Weather is part of the picture at sea. Let us start with storms. A hurricane is a big storm with strong winds. It forms over warm ocean water. A storm is called a hurricane when its winds reach 74 miles per hour. Atlantic hurricane season runs from June 1 to November 30. The first weather satellite was launched in 1960, so in the 1940s nobody could watch storms from space. Before weather forecasts got better, ships in the area had less warning about storms than ships have today.

The sea has its own features. The Gulf Stream is a stream of warm water. It carries warm water north along the coast of Florida and then across the Atlantic Ocean. The Caribbean has many islands. They make wide areas of shallow water that can be hard for big ships to steer through. In the 1940s, ships and planes found their way with compasses, charts, dead reckoning and radio direction finders. A compass needle follows Earth's magnetism, which helps people tell which way is north.

Magnetic declination is the angle between magnetic north, where a compass points, and true north, the direction of the North Pole. It is different from place to place. It slowly changes over time, because magnetic north keeps shifting. Christopher Columbus wrote in 1492 that his compass readings were odd while he sailed through this part of the Atlantic. Some writers say true north and magnetic north lined up in part of the Bermuda Triangle long ago, which could have thrown off sailors' and pilots' navigation. When you hear a famous story, where could you look to check it?

Words to know

• declination: compass angle
• navigation: finding your way
• insurance: money protection
• satellite: orbiting machine
• shallow: not deep