2 Best Sights in Ilha Grande, Side Trips from Rio

Locals and visitors alike regard Lopes Mendes, a 3-km (2-mile) stretch of dazzling-white sand lapped by emerald waters, as the most beautiful beach on Ilha Grande. It's often cited as one of the most beautiful in all Brazil. Strict environmental protection orders have kept the jungle-fringed beach from being spoiled by development: expect makeshift beach kiosks, not upscale bars. Take a taxi boat from Vila do Abraão (R$30) if you don't feel up to the two-hour hike through the forest, or hike here and take the boat back—the rough jungle trail and sticky heat can tax even the most hearty of ramblers. While here, use plenty of sunblock, as the rays rebounding off the white sand are particularly strong. If you want to avoid the boatloads of day-trippers, go early. Amenities: food and drink. Best for: swimming; walking.

If you want to avoid the boatloads of day-trippers, go early.

With its pristine white sands and turquoise waters, this beautiful, secluded beach starkly contrasts the dark prison ruins behind it. Visitors have the place practically to themselves, as few people make the arduous 7-km (4-mile) trek through the hot jungle to get here. Those who do are rewarded with one of the island's most gorgeous beaches and the sense of achievement that comes with really getting off the beaten track. The prison ruins are worth exploring, but be sure to head back several hours before sundown.  Amenities: none. Best for: solitude.