Just off Zanzibar’s coast, Mnemba Atoll is a marine Eden—a ring of coral where sea turtles, parrotfish, and neon nudibranchs drift past in a kaleidoscope of color. Dive into the aquarium-like shallows, or snorkel alongside spinner dolphins at sunrise. Nearby, Prison Island (Changuu) hides a darker past—a 19th-century quarantine station now home to giant Aldabra tortoises. Feed these gentle giants, then picnic under century-old fig trees, gazing back at Stone Town’s skyline.