Expected to generate huge amounts of electricity and control flooding on the Yangtze River, Others rue the construction of the Three Gorges Dam in China. Some at the radical end of the spectrum would like to see Utah's Glen Canyon Dam blown up, unleashing the once-wild Colorado River and draining 186-mile-long Lake Powell. This explains in part why such projects are increasingly controversial among environmentalists. Places appear and disappear when hydroelectric facilities are built, damming rivers and creating lakes where there were once valleys. Global warming, which is thought to be raising ocean levels, imperils low-lying islands and littorals from the North Atlantic to the South Pacific. When the tide goes in or out, you still can hear their old church bells ring, he says. Norman Thrower, a professor emeritus of geography at UCLA, adds to the list the slowly encroaching ocean, which has engulfed coastal hamlets in southeastern England. Natural disasters such as earthquakes, floods and volcanic eruptions have swept away such places as the Krakatoan islands and half of Santorini, now a crescent in the Aegean Sea edging the caldera of the volcano that formed the Greek island. To console myself and better understand why places aren't as permanent as I think they ought to be, I turned to geographers, who cite a variety of reasons that towns, countries and geographical features disappear from maps, even though they might remain in history books and memory.

That's the romance of places off the map. The more gone Bessarabia is, the more I want to see it. Similarly, I want to see the majestic spires of Glen Canyon on the Colorado River in Utah, which were obliterated after the construction of Glen Canyon Dam Tibet before the Chinese takeover and scads of places in Eastern Europe I've read about but can't find on maps: Pomerania, Volhynia, Bukovina, Courland, Bessarabia, all of which sound like the homelands of nutty dukes and counts in Marx Brothers movies. I would like to visit Prussia, for example, which has a long history but no longer exists on modern maps.

Road to nowhere oracle