The Florida Keys are known for many things, but cavern diving isn't one of them. Maybe it should be. Minnow Cave, Pennekamp Park, Key Largo. Motionless on the bleached sandy bottom, I'm watching a school of coppery glassy sweepers glide through dappled sunbeams at the cave entrance. A Nassau grouper hovers at the edge of my peripheral vision adjacent to an immense coral crab. Moving forward, my pupils dilate, adjusting to the dim light, revealing even more details within the cavern. I turn on my underwater light and pan it slowly over the ceiling and walls, each square foot a marvel of saturated colors. The beam reveals encrusting sponges, fan worms, hydroids, flame scallops and algae.My slow exhalation - part awe and part controlled breathing so as not to disturb the inhabitants of this sacred place - releases shimmering bubbles that form reflective, metallic-looking pools on the ceiling. I move forward very slowly with nearly indiscernible fin flicks so as not to swirl sandy sediment that would hinder visibility. Fortunately, most of the bottom debris here is seashell bits and coral gravel, thick and heavy debris that does not stir up readily.Therisa maneuvers toward the left entrance where the light is streaming in from above and behind. Peering through my camera viewfinder I'm reminded why we named this cave on French Reef ''The Cathedral.'' More than a mere coral grotto, it is a cavern made majestic by its high, twin seaward portals. Like Renaissance-period stained glass windows, these openings let sunlight refracted by the sea's surface, stream to the floor in beams of flickering polychromatic pools. Its elongated, inshore opening beckons all that approach with the promise of the unknown.The cavern's 30-foot depth affords us both long bottom time to explore nooks and crannies filled with subjects for Therisa's macro lens while I play with different angles for composing and lighting wide-angle pictures.Decades ago, when I first visited these same caves I would charge through these caves mesmerized simply by the experience of passing under and through the reef itself. Mea culpa. I've since learned to savor the experience and notice the little things, the miniature treasures within the shadowy recesses.An hour later, our film spent, we exit. Squinting in the brightness of the open water, we laugh at the residual air bubbles now seeping up through the cavern's ceiling and out through the porous reef.On the surface it's one of those steamy, sultry June days when the Florida sun has beaten the surface into submission with oppressive heat and nary a cloud is in sight to provide even a modicum of shade. These are the surge-free days best for diving the cooler waters of Gulf Stream bathed reefs and exploring the shallow and safe swim-through caves off Key Largo. Every dive reveals something new and a trip to a topside reference book. ''Did you see that camouflaged four-inch creature lying in wait?'' exclaims Therisa. ''Was it a holothuroidean or some kind of mollusk?'' It's true, the more you know the more you realize you don't know. Shallow cave exploration has revealed many creatures unknown to us during daytime reef swims and we often flip through the reef guidebooks during surface intervals attempting to identify some creature we have never seen before.French Reef contains several caves besides The Cathedral. It's only three mooring-buoys distance south to Hourglass Cave, the destination of our second dive.The smaller, more concealed openings of this cave make it more difficult to locate but the rewards are certainly worth the effort. More compact and tube-like, the interior passageway narrows in the center on both sides and then expands outwards again.While daylight is always visible at the opposite end, it's darker here than in Cathedral and a good dive light is needed to divulge this cave's hidden gems. Copper sweepers, grouper, crabs and a resident green moray keep our attention focused. The tubular corridor makes for dramatic photos for framing a diver holding a light, backlit by the sun at the cave's exit.We cast off from the mooring buoy at French Reef and plot a course farther north and inshore off Key Largo to Minnow Caves. During June and July these mini-labyrinths host millions of silversides, inch-long, dwarf herring baitfish. The shallow 20-foot depths of this inshore reef give no indication from the surface to what wonders lie beneath.As the bubbles from our giant-stride entry clear, veils -no, call them walls - of baitfish obscure the reef we know is somewhere on this ever-moving monolith of fish.The living wall parts as we languidly angle our bodies to where we think the cave entrance is located. It's difficult to imagine the ocean more alive as the silversides pulsate around us. Glancing back, the curtain has closed, yet not even a single fish has brushed against us. The small cave beckons us and we share the entry with legions of fish moving through the opening like a blob of mercury through a narrow test-tube.I motion to Therisa to position herself at this opening while I swim over the reef crest to enter on the opposite side, knowing full well I'll never be able to portray the essence of this experience on film. With Therisa visible at the far side entrance, we begin slowly working our way towards each other triggering our cameras whenever we become momentarily visible through the flowing schools. The fish are creating their own chorus as they move in primordial harmony through the grotto.Both film and minds are exhausted when we meet. It's been another astounding day in less than 20 feet of water. But it's far from over. Outside the cave we happen into barracuda, the greyhounds of the sea, flashing through the school picking off hapless silversides one at a time. It's a thrilling spectacle that jolts our weary bodies with enough adrenaline to keep us chattering during the entire boat ride home.Often overlooked, rarely savored, the caves of Key Largo will continue to both delight and consume our interest for many years to come. WHERE TO GO: Key Largo, Florida. Nearly all of the dive operators will know where to find the caves at French Reef, however the true key to your enjoyment will be to request your own extended stay in each cave, rather than a quick swim-through tour. Smaller charter boats may be more willing to grant this request. Better yet, plan your dives during weekdays when charter boats are usually not as busy and have more time available.As is the case all over the diving universe, local names for dive sites often vary by operator or divemaster. Such is the case here, so we can only offer the names most commonly used by the majority of experienced operators. However, all the operators will know where the mooring buoys are located.French Reef: Hourglass Cave, off mooring buoys F1 and F2. Christmas Tree Cave, off mooring buoy F3. Hole in the Wall, off mooring buoy F4 and The Cathedral (also referred to as Sand Bottom Cave), off mooring buoy F5. There are several other smaller swim-through caves in the area, especially North of mooring buoy F5. Minnow Caves is at North Dry Rocks, a half mile north of the heavily dived Christ Statue between the center buoys. The are other smaller and shorter swim-through caves at The Elbow, Carysfort Reef and Molasses Reef. WHEN TO GO: Any time of the year. The best dives will be during periods of relatively calm surface seas to optimize observation within the caves without surge. If you want to see the silversides go as early as mid-May and as late as mid-August. The peak months are June and July. FOR MORE INFO: For more information about diving the coral caverns of the Florida Keys, click on the home pages below.
Find exclusive opportunities and packages offered to Society members on the member benefits site.