Timbuktu

"What struck me most powerfully when I got to Timbuktu was that the streets were of sand. I suddenly realized that sand is very different from dirt. Every town starts with dirt streets that eventually get paved as the inhabitants prosper and subdue their environment. But sand represents defeat. A city with streets of sand is a city at the edge.

That, of course, is why I was there: Timbuktu is the ultimate destination for edge-seekers. Of the half-dozen places that have always lured travelers with the mere sound of their name—Bali and Tahiti, Samarkand and Fez, Mombasa and Macao—none can match Timbuktu for the remoteness it conveys. I was surprised by how many people, hearing of my trip, didn't think Timbuktu was a real place, or, if it was, couldn't think where in the world it might be. They knew it well as a word—the most vivid of all synonyms for the almost unreachable, a God-given toy for songwriters stuck for an "oo" rhyme and a metaphor for how far a lovestruck boy would go to win the unwinnable girl. But as an actual place—surely Timbuktu was one of those "long-lost" African kingdoms like King Solomon's Mines that turned out not to exist when the Victorian explorers went looking for them."
(On Writing Well, William Zinsser)