Here’s an odd bit of African geography: The finger of land in the upper left is Namibia, the region at the top is Zambia, Zimbabwe is at bottom right, and Botswana is at bottom left. Is the border between Zambia and Botswana long enough to permit a bridge to be built between the two? Or do the two peninsulas intrude far enough to make this impossible?

The answer isn’t clear. In 1970 Namibia had insisted that the four nations meet at a single point, meaning that the Kazungula Ferry linking Botswana and Zambia was illegal, as the border between them had no breadth. After an armed confrontation the ferry was sunk. Thirty-five years later Botswana and Zambia proposed building a bridge where the ferry had run. Is that geometrically permissible? The shaky consensus is that the two nations share a brief boundary of 150 meters between two “tripoints.” But the truth is as murky as the Zambezi itself.

(See Point of Interest. Thanks, Steve.)

In 1966, a group of teenagers in the town of Paulding, on Michigan’s Upper Peninsula, reported seeing a ghostly light in a valley nearby. Locals claimed that the light, which appears every night when viewed from a precise location, was the lantern of a ghostly railroad brakeman who had been killed trying to warn an oncoming train of railway cars stopped on the track.

A more prosaic explanation is that the specter is produced by the headlights of cars traveling on US 45, about 5 miles away. In 2010, a group of student engineers from Michigan Tech studied the light with a telescope and distinguished individual vehicles and even an Adopt a Highway sign. They were able to produce the effect themselves by driving a car along the suspected stretch of highway. It’s thought that an inversion layer may create a volume of unusually stable air that accounts for the lights’ visibility at such a distance.

That didn’t end the ghost theory, though. “We’ve been told we haven’t seen the real Paulding Light,” Ph.D. candidate Jeremy Bos told Michigan Tech News in 2010. “I’ve been out there 15 times, hours at a time, in the heat, the cold, and the rain. It’s always the same. We were there Monday with a man who saw the headlights on our computer, and he refused to believe it.”

“No matter what, some people will believe what they want to believe.”

A thousand miles off the coast of West Africa, where the equator crosses the prime meridian, lies a nonexistent point of land known as Null Island. It was invented by GIS analysts to help trap errors: When software converts misspelled street names, bad building numbers, and other faulty data into coordinates of latitude and longitude, the result is often 0°N 0°E — which led cartographers to joke that there’s a 1-square-meter island in the Gulf of Guinea where all these lost features reside. (In fact what’s there is a weather observation buoy, above, which must wonder what all the fuss is about.)

Related: Conceptual artists Terry Atkinson and Michael Baldwin considered a map on which the areas that we normally call Arizona, New Hampshire, Tennessee, etc., are instead labeled “Not Arizona,” “Not New Hampshire,” and “Not Tennessee.” This would have to be regarded as simply false, or at least as inviting new names for these places.

“Yet such a scheme would be correct if, for example, the delineated area normally named Arizona was labelled ‘Not New York’ and so on throughout the whole map synopsis. Only this time the map would be a map to indicate what was not where rather than the conventional what is where. Where there is no road in a certain place we do not conventionally indicate this fact upon the relevant map by labelling it ‘There is no road at this point.'”

(From Jeffrey Kastner and Brian Wallis, Land and Environmental Art, 1998.)