My wife, Ronni, and I were stumbling along a muddy path in a dense lowland rain forest on Sulawesi—one of Indonesia's 17,500 islands—seeking something found nowhere else on Earth: a spectral tarsier, among the world's smallest and rarest primates. We'd always assumed that hiking through remote jungles in search of endangered wildlife and ancient cultures required a major expedition. Then we spent ten days in Sulawesi. Volcanoes fume above its rain forests; indigenous tribal customs are treated like national treasures; some of the world's greatest marine diversity is accessible just offshore; and on that evening's hike into the lush Tangkoko-Duasudara Nature Reserve, on the island's northern tip, we were trekking among an assortment of creatures that inspired British naturalist Alfred Russell Wallace to conjure up his theory of natural selection (contemporaneously with Charles Darwin) during his travels here in the mid-1800s.
The trail tilted uphill, swooped left, and we found ourselves standing beside a column of strangler fig roots, which grow down from the canopy and eventually choke their host tree, leaving only a hollow where it once stood. We followed our guide, Iwan, deeper into the undergrowth until we spotted our quarry among a gnarl of roots: a tarsier, the size and color of a puffed-up mouse. It grasped the bark with long, wire-thin fingers and twisted its head to gawk at us. Then, boing! boing! off it went, leaping from tree to tree.
On the hike down, the moon lit our path. A native scops owl whooped in the night. This place isn't just wild, we realized, it's as close to unearthly as solid ground gets.
Going Guided: Local outfitters, like Manado Safaris, can arrange all lodging, transportation, and guided activities (manadosafaris.com).
DIY: If going it alone, remember that the terrain can be rugged, rural roads punishing, and parkland trails inconsistently marked. But the rough edges are what turn a trip to Sulawesi into an authentic adventure.
Sulawesi's big city is hectic enough to revive even the most jet-lagged zombie. Mopeds and pedal-powered rickshaws swarm the streets, and shops vie for space with restaurants reputed to be among the country's finest. Lie low on the waterfront in one of Hotel Pantai Gapura's floating cottages built in traditional island style ($59; asiarooms.com). The nearby open-air market specializes in local fare—dogs and rats included. But the fishmongers hawk more palatable ingredients, and the cooks at even the higher-end restaurants will prepare a freshly bought catch to order.
In the tropical rain forest, a half day's drive north of Makassar, vanilla and pepper plants scent the air of highland base town Rantepao, home to the indigenous Toraja people and their unique Aluk To Dolo (Way of the Ancestors). T-shirts and digital cameras are standard now, but tradition hasn't lost its grip. Locals like Benny Rantelili guide day hikes through dense jungle to rice paddies lined by distinctive Toraja homes, with prowed teak frames and hieroglyphs etched into their facades detailing the occupants' life stories ($215 for a three-day tour, including meals and lodging; sulawesi-cendanatours.com). After prowling villages accessible only by foot—and possibly paying respects at a Toraja funeral (see below left)—the Toraja Heritage Hotel is a welcome cooldown ($182; torajaheritage.com). Sip a cold local brew on the veranda and contemplate the harmony of old ways and new.
The first thing visitors usually notice is the Toraja's welcoming attitude to visitors; the second, their necro-centric culture. All around, set into niches in limestone cliffs, are tau-tau: effigies of the deceased. Attending one of the funeral celebrations is a macabre privilege. After the wake—given over to chants, dances, and the ritual slaughter of a water buffalo—the Toraja scale cliff faces with the cloth-wrapped remains of their kin and place them in caves behind the tau-tau to be enshrined in the landscape as daily memento mori.
After a short flight from Makassar to North Sulawesi's capital, Manado ($96; garuda-indonesia.com), and a 50-minute boat ride out into the Celebes Sea, divers and snorkelers can plumb the hot spots of Bunaken National Marine Park—a volcanic archipelago set amid 300-plus surface miles of thriving tropical reef. Many of the islets have been claimed by dive resorts, which specialize in guiding guests to the reef's most vibrant corners—canyons, cliffs, and deep coral shelves prized by divers the world over. But there's also prime beach-basking territory, with predictably tepid water and white-coral sand that feels not unpleasantly like Grape-Nuts underfoot. Siladen Resort & Spa (pictured) has five waterfront bungalows and a state-of-the-art dive center on tiny Siladen Island. Days are spent diving the surrounding marine reserve from one of the resort's four boats and otherwise lounging idly in the shade. Nightlife: a private barbecue and sunset snorkel ($540; siladen.com).
Cruise the archipelago by moonlight and dive a new spot each day on one of Murex Dive Resort and Liveaboards' fully equipped floating base camps ($333 a day for two, including meals, airport transfers, and gear rental; murexdive.com). The M.V. Serenade sleeps 12—the sloop-rigged M.S. Symphony, six—in air-conditioned cabins with hot showers. Zodiacs are on call for runs to reef shelves and cliffs, where sea snakes, blue-ringed octopuses, sea turtles, and thousands of other pelagics ride the rich Celebes Sea currents. The only thing better than rolling out of bed for a cup of coffee and a Sulawesi sunrise is a rollback entry into the globe's unparalleled aquatic ecosystem.
A bumpy two-hour drive east of Manado is the Tangkoko-Duasudara Nature Reserve, 34 square miles of biodiversity sprawling in the shadow of its 3,770-foot namesake volcano. The rain forest shelters species as diverse as the spectral tarsier; the babirusa, a wild pig with outrageously curled tusks; and the maleo, an endangered bird that incubates its eggs in the reserve's geothermally heated black sand. Knowledgeable rangers congregate daily at the park entrance, offering their services ($10 for a half day). A bungalow homestay at shabby-chic Mama Roos, just outside the gates, grants immediate access to trails through Tangkoko's lush canyons ($10 a night, including meals; aktun.com/mamaroos). For a view from an active volcano, head to the village of Tomohon in the Minahasa highlands for an hour-long hike to Mahawu's 4,344-foot rim or a two-hour hoof to the crater of Lokon (5,184 feet).
Since the Bali bombing in 2005, a travel warning has been in effect for American citizens in Indonesia. On Sulawesi, conflict between Muslims and Christians has been largely confined to the island's central province, an area bypassed by this Big Trip.
The U.S. Department of State issues updated travel advisories (travel.state.gov), and the Indonesian Tourism office can provide safety recommendations and help arrange guides and transportation within the country (indonesiatourism.com).