It’s strange to think about, but the landscape of our world won’t always be the way it is now; it’s easy to fantasize about technologies changing in the future, but what about the city you live in? Stranger still to think that, like Pompeii and other disappeared cities of the past, some of our comparatively sturdy urban areas might go the way of the Dodo as well; Detroit, as I’ve often blogged, is headed that way as we speak (its population now is 1/3rd less than in 1950 — and shrinking). But what other metropolitai are starting to look like future archaeological digs? Here are some of the most surprising answers from Forbes.com’s article.

Mexico City, Mexico

Mexico City is sinking, though not into the ocean. The city sits on an aquifer, which is also its main source of drinking water. Each time one of its 20 million inhabitants takes a drink of water, the city sinks a tiny bit more. By some estimates, parts of the city have fallen 9 meters in the last 100 years. Potentially even worse: The aquifer is thought to be running dry. Although Mexico City is currently growing at a rapid clip, a dwindling water supply on sinking ground could quickly reverse the trend.

Naples, Italy

You thought Pompeii was a one-time thing? Think again: Mount Vesuvius, which destroyed the Roman city of Pompeii in A.D. 79, erupts about once every 100 years. It last erupted in 1944. Vesuvius sits on the Gulf of Naples in southern Italy, which is home to more than 4 million people. That includes those in the city of Naples itself, as well as more than half a million people in the “red zone” closest to the mountain–folks certain to die if not evacuated in time. (San Francisco is another disaster-prone city; researches guess that it’ll be hit by an earthquake as large as the one that destroyed it 100 years ago by 2086.)

Timbuktu, Mali

If things keep going like they’re going, before long Timbuktu is going to be a “deserted” city in more ways than one: desertification, in which sand dunes swallow greener land, is a problem in several countries on the southern fringe of the Sahara. One of the cities most threatened is Timbuktu in Mali, a 1,000-year-old settlement that was a major center of Islamic learning during the 15th and 16th centuries. Several projects are under way to try to “re-green” the land with tree plantings and the like, but some parts of the city are already half buried in sand.