Whale bar at Vommuli. [Photo by Zhao Xu and Feng Tianyi/China Daily]

A week after my snorkeling trip I listened as a friend, a frequent beachgoer, recalled his most memorable underwater experience. "I swam and swam, going further and further out into the ocean while admiring the schools of fish that appeared in every color, shape and iridescence that I could possibly imagine. Even the sea around me changed its hue－from aquamarine to peacock blue and then to sapphire.

"But then suddenly, as if I had unwisely stepped inside some invisible door leading to the secret chamber of Poseidon, the sounds and sights receded. Instead, a much darker color reigned, color that absorbed and dissolved every shaft of sunlight. That's the real underwater world: cold, strange and sealed-off. It's not a world that gives one the feeling that you can come or go at will.

"I was scared."

Indeed, caution does come, and often when you least expect it. Another member of the hotel staff, an Indian whose hometown is just two hours away from the Maldives, recalled for me his experience wandering alone on the island late one night.

"I was suddenly struck by fear and I didn't know why," Reji Sebastian said. "I heard the rustling sound of banana tree leaves and told myself that I had better go back to the hotel."