by Mark Kaufman
When swimming in the waters of the isolated Chagos archipelago in the Indian Ocean, a half-dozen sharks would sometimes surround Francesco Ferretti.
"You are in another world," said Ferretti, a marine ecologist at Hopkins Marine Station of Stanford University. "You feel like you're in one of the last remaining paradises of the planet."
The medium-sized reef sharks here are harmless (to humans). The coral is vibrantly colored. The water pure.