When the weather gets hot (and it does), take to the natural swimming pools. Close to Lençóis, and so popular that there are now beer and refreshment stands lining its banks, is the Mucugezinho River. Below these stands on the same river is a deep cold pool called the Poço de Diablo. South of Lençóis, near the town of Andaraí, is an underground pool with crystal-clear water and excellent limestone formations called the Poço Azul, where swimming is allowed.
Swimming is not allowed at the Poço Encantado, and it's a long way from anywhere down some pretty bad roads, but it's worth seeing anyway. It's a large underground cavern with crystal-clear water. Between April and August light reaches down through a hole in the cavern wall, and the water glows electric blue.
For wildlife watchers there's the Marimbus wetland. In addition to lots of caiman, it is also home to capybaras and a wide variety of colorful bird life.
Rony Bike (tel. 075/3334-1700) offers guided mountain-bike trips and also rents bikes. Owner Rony Oliveira has lived in the area for over 10 years and biked every possible trail. The cost for one person including a bike and guide is R$75 per day. Itineraries can be customized to suit all interests and abilities. Adilson Trilhas, Passeios e Bikes, Praça Samuel Sales 32 (tel. 075/3334-1319), is another option for mountain-bike tours and rentals.
Trails in the Chapada Diamantina are quite good -- many are old miners' supply routes -- but signage is nonexistent. Carry a map, compass, and some spare food and water (locals insist the water from the highlands is drinkable, but there are enough cattle still pastured up there that I have my doubts). If in doubt of your trail-finding skills, bring a guide along. To locate a guide, try the tour agencies below or contact the guide association directly: ACVL (Associação dos Conductores de Visitores no Lençóis), Av. General Viveiros 61, across the river by the Cantos dos Aguas Hotel (tel. 075/3334-1425). Roy Fuchs Specialized and Personalized Guide Services (tel. 075/3334-1305) is another source of guide information. Roy is American, but has lived in the area for years.
There are dozens of hikes in the Chapada Diamantina. The following are just suggestions. A short hike up the Lençóis River from the bridge will take you to the Serrano swimming holes, composed of little pools of pink conglomerate rock. About .5km (1/4 mile) farther up the river, there's the larger Hartley natural pool. A short, pretty walk beyond that a small tributary comes in from the right, the Grizante Creek. Follow that up and you'll come to Primavera Falls.
An hour's walk south of town will lead you to the Ribeirão de Meio natural water slide. The water slide is also the trail head for a long (8-hr.) hike along the banks of the Ribeirão River to Sossego Canyon and Sossego Falls.
A good day hike that will take you through the heart of the Chapada is the 25km (16-mile) trek from the Capão Valley to Lençóis (or vice versa). Done from Lençóis, it's possible to get an 8am bus to Palmeiras (R$6) on the far side of the Chapada, then hire a cab to take you over the rough gravel road to the trail head (R$40). The hike takes about 8 hours and provides some excellent views.
For horseback riding, find one-armed Taurino Sousa Alcantera in his souvenir shop at Rua das Pedras s/n, about halfway up the street (tel. 075/3334-1403). Itineraries include a 5-hour ride to the Rio Capivara (R$60), a short 40-minute ride to Ribeirão de Meio (R$30 per person) where you can then play on the natural water slide, and an 18km (11-mile) daylong ride through several rivers to the Rio Roncador (R$90 per person).
A popular sport in Brazil, rappelling is the act of lowering yourself down a length of rope with a harness and a locking carabiner. You can rappel down a cliff face, a waterfall, into a cave, whatever. In Lençóis, the rappelling specialist is Nativos da Chapada, Rua Miguel Calmon 29 (tel. 075/3334-1314 shop, or 9960-0131 cellphone). The company offers a number of different rappel outings, including a 30m (98-ft.) drop down the Alto da Primavera Cliff, a 48m (157-ft.) descent into the Gruta do Lapão Cave, a 150m (492-ft.) descent from the Pai Inácio Mesa, or a soaking 50m (164-ft.) drop through the waters of Mosquito Falls. On most outings you get to make six descents. Cash only; prices range from R$80 to R$140 (for two-four people).
Lentur, Avenida Sete de Setembro (tel. 075/3334-1271; www.lentur.com.br), offers seven different guided minivan tours to just about all of the local caves, springs, waterfalls, and mesas (Lapa Doce, Gruta Azul, Poço do Diable, Poço Encantado, and so on). Tours are in eight-passenger minivans. They begin at 8:30am and end at 6pm, and include a light lunch. Minimum group size is four. Cost for each tour is R$65, including the services of a Portuguese-speaking guide. An English-speaking guide costs R$90, with that cost divided by however many require his services.
Lentur also does guided trail hikes for groups of up to six people. Included is a guide and transportation to and from the trail head. The prices range from R$60 to R$120 per day for the trip (not per person). Trips include the 1-hour walk to Ribeirão de Meio, the 3-hour walk to Sossego Falls, the 4-hour walk to and through Lapão Cave (bring a flashlight), the 8-hour walk from Capão to Lençóis, and the 5-hour walk from Pai Inácio Mesa to Lençóis. There is also a 3-day hike to Cachoeira da Fumaça in the center of the Chapada. Cost is R$110 per person per day, including meals and guide. A sleeping bag is required.
On the main square, Venturas & Aventuras, Praça Horácio de Matos 16 (tel. 075/3334-1304; www.venturas.com.br), is run by English-speaking guides. Slightly less volume-oriented than the above two companies, they are also somewhat more expensive. In addition to 1-day trips, this company also offers a number of 2- and 5-day trekking packages.