As they span significant areas of Asia, Europe and the Americas, karst landscapes cover some 15 percent of the Earth’s land mass. Scientists estimate that these areas of porous bedrock are home to as ...

In the 1890s B.C. newspapers sometimes put out big maps as promotional items. Alas, over a century later they’re as rare as hen’s teeth. But every once in awhile you come across an ad for one, and can ...