Without the unique geologic structure of the inland blue holes—deep, dark, sheltered, with little tidal flow—specialized bacteria studied by Macalady would never have gained a foothold.

Discover the mysterious depths of Jacobs Well Natural Area in Texas, a chilling swimming spot with a spooky reputation. Dive ...

For while the city jingled, beneath the mayor’s feet was Philadelphia’s deep, dark financial hole. Because Philadelphia had run out of funds with which to buy rails and cars, two other subways ...