A quadripoint is a place where four territories meet at a single point, like Four Corners National Monument in the American Southwest. There is probably no four-country quadripoint in the world today, though one in Africa comes close and Europe arguably had one until World War I. But what if we throw provinces, counties, townships, and all kinds of other little prefectures into the mix? What's the world's most complicated multipoint? The answer is actually a UNESCO World Heritage site—and one of the most beautiful views in Europe.

Florida has America's only "quintipoint."

There's one place in the United States where five counties meet at a single point: the middle of Lake Okeechobee, in Florida. The whole lake belonged to Palm Beach County until 1963 when the other countries, mad that Palm Beach County was padding its area (and therefore its share of state highway funds), appealed to the state legislature to slice up the lake like a pie.

You can see Mount Etna from most of eastern Sicily.

But that's nothing compared to Mount Etna, the tallest and most active volcano in Europe. Its frequent eruptions and eerie, glowing lava flows inspired the ancient Greek myths that that terrible monster Typhon was raging beneath the volcano, and that the fire-god Hephaestus ran his forges inside. Today Etna is popular with hikers and wine lovers visiting the vineyards at its feet. Between November and March, its two ski resorts are open. You ski on an active volcano one day, and hit the beach or sail the Gulf of Catania the next.

Ten different towns share one peak.

On Mount Etna, lava, steam, and ash regularly keep hikers from ascending all the way to the summit. But to the map nerd, the peak is unique even when it's quiet. The Italian province of Catania is divided into 58 comuni, or municipalities, and ten of those—Adrano, Biancavilla, Belpasso, Bronte, Castiglione di Sicilia, Maletto, Nicolosi, Randazzo, Sant'Alfio, and Zafferana Etnea—all meet at the top of the volcano. (Bronte, named for one of the legendary Cyclops said to work Etna's forge, touches the peak on the west and the northwest, so the peak is actually divided into eleven wedges!) So Etna is the only "decipoint" on the planet, and the most complicated border vertex anywhere.

If, that is, you ignore the craziness at the bottom of the world.

The Antarctic Treaty of 1961 allows all nations freedom to explore and do research on the world's coldest continent, but it doesn't address the past territorial claims made by seven countries. So technically, all those Antarctic claims are still equally valid. Since they all meet at the South Pole, the world's southernmost point is a complicated 11-way intersection where various territories, overlapping claims, and unclaimed land all meet. But tourists should know that it's much less picturesque than Sicily, and the pasta isn't as good.

Explore the world's oddities every week with Ken Jennings, and check out his book Maphead for more geography trivia.