On the way down I saw nothing. The water was a blur of teal fringed with rusty shadows, darkening, about twenty feet below, to a sickly emerald. I followed a rope strung between a buoy and a stake in ...

Nat Geo Explorer Tara Roberts quit her job, learned to dive, and now helps discover the underwater wrecks of slave ships around the world with an incredible group of Black conservationists. National ...