Lake Malawi, a 2,300-foot-deep, 11,400-square-mile gem in southern Africa, is home to 1,000 species of fish—one of the highest concentrations on the planet. It's also the site of half-mile-wide, 250-acre Mumbo Island, one of our favorite out-there getaways. The lake was declared a Unesco World Heritage site in 1984, and once you get underwater it's easy to see why. There are more than 400 types of brilliantly colored freshwater tropical fish, like damsels, angelfish, and wrasses. Guests can snorkel or scuba with them past sunken knolls of granite boulders or kayak to the lake's dozen islands for what Cape Town, South Africa–based Kayak Africa calls the top sea-paddling route in southern Africa.
Best of all, the outfitter limits occupancy to 14 guests at a time, putting them up in six furnished bungalows and tents with hammocks, thatched-reed roofs, and hot bucket showers. It's bare-bones—there's no electricity—but that's by design. Wilderness Safaris claims that if all tents and decks were removed, there wouldn't be a human trace within a year. There's also plenty to do on dry land. You can watch the hundreds of white-throated cormorants that nest on Mumbo or hike its five one-to-two-mile nature trails past rock fig and baobab trees. But after you've had a full day in and on the water, we won't blame you if you just want to rest in that hammock. From $195 per person per night, all-inclusive.
Access: Fly to Malawi's Lilongwe International Airport (South African Airways connects through Johannesburg), drive four hours to Cape Maclear, on Lake Malawi's southern end, and take the 45-minute ferry ride to the island.