Near the famous Arch of Cabo San Lucas, one of the ocean’s most extraordinary and least-known phenomena quietly unfolds. Along steep underwater cliffs, sand flows like water, pouring endlessly into the deep blue canyons below. These are the sandfalls of Cabo — underwater cascades made not of water, but of sediment. To divers, they look like gravity itself has come alive on the seafloor. Grain by grain, the sand slips over the edge, forming shimmering curtains that drift downward into...

In the deep blue lies one of the ocean’s most majestic creatures: the giant manta ray  ( Mobula birostris ). With wings that can span...

The Sea of Cortez, known as “the aquarium of the world,” is home to an incredible variety of marine life — from playful sea lions to...