The ensuing isthmus proved transformative, forcing warm, equatorial current from the Gulf of Mexico into the Atlantic and up the North American coast as the Gulf Stream.

Madison is an isthmus. The city is so narrow you can walk from Lake Mendota to Lake Monona in about 15 minutes. Seattle, which connects Lake Washington and Puget Sound, is another large isthmus in ...

The isthmus, a narrow strip of land separating the Gulf of Mexico from the Pacific Ocean, has long been recognized for its strategic potential. As far back as the 16th century, Spanish ...