The Fens: England Below Sea Level
Global sea levels are rising. This shouldn’t be news; they’ve been rising for 20,000 years, going up 300 feet since the last Ice Age, when glaciers covered Siberia and Canada. As it turned out, Britain was pretty awful during the last Ice Age, and people avoided it; mile-thick ice caps had something to do with it. When people did start appearing about 100 centuries ago, sea levels were still 150 feet below the present level, and the new settlers simply walked over from Europe; the Dover-Calais ferries now float high above their paths.