A friend of mine once told me that looking at the ocean from shore was like looking at the outside of a circus tent. Scuba diving is to pull back the flap and step inside. Once I took up diving, I realized he was right. For the past 15 years, my wife, Gishani, and I have been venturing under the big top, watching with wonder the spectacle of color and performance on coral reefs all over the world. Still we come back to Bonaire, the tiny arid island in the southern Caribbean, year after year. It doesn?t boast the megafauna of the Maldives, the wrecks of Truk Lagoon, or the gin clear waters of the Red Sea. But it remains our favorite. In Bonaire, scuba diving can be practiced as it was in the earliest days of the sport: wading in off a beach with a mask and fins to explore a new patch of reef, using your own skills to navigate, then swimming back, swapping tanks, then setting off down the coast to find the next place to dive. This kind of casual but adventuresome diving used to be called ?reefcombing? and I think it describes it well, distinguishing it from exploring shipwrecks, or deeper, more technical pursuits. The diver kicks over the reef, watching the sergeant majors defend their egg patches, the moray eels gape their menacing mouths to pump water over their gills, and a swarm of blue tangs flow across the coral like an indigo ribbon. If you?re lucky, an octopus, nurse shark, or sea turtle will grace you with its presence, then disappear just as quickly. At a mere 30 o...