What is it?

Odzala-Kokoua is a 13,500-square-kilometre wilderness of Congo Basin rainforest, flooded savanna and mineral-rich forest clearings known as 'bais' — a place so remote that much of it has never been walked by outsiders. Here you trek on foot behind Ba'Aka and Congolese trackers through cathedral-like Marantaceae forest, following the knuckle prints and night nests of habituated western lowland gorillas until, quite suddenly, a silverback the size of a boulder is sitting fifteen metres away, chewing leaves and regarding you with unhurried curiosity. At dawn the forest is a wall of sound — grey parrots screeching overhead, hornbills beating the air like tiny helicopters, the distant boom of a forest elephant. Wade barefoot through the shallow, tea-coloured waters of Lango Bai and you'll find yourself sharing the clearing with buffalo, bongo antelope and elephants that emerge silently from the treeline. Unlike the mountain gorilla treks of Rwanda and Uganda, Odzala receives only a few hundred visitors a year, which means no queues, no crowds and an almost eerie sense that you have the Congo to yourself.

Where is it?

The park lies in the far northwest of the Republic of the Congo (Congo-Brazzaville), in the Cuvette-Ouest region near the Gabon border, deep within the world's second-largest rainforest. Visitors typically fly from Brazzaville to the Mboko airstrip on a chartered light aircraft, then travel by 4x4 and boat between the three flagship camps — Ngaga (for gorilla tracking), Lango (for bai wading and savanna game) and Mboko (for river and forest safaris). The main dry seasons, roughly June to August and December to February, offer the best trekking conditions and easier road access, though the forest is green and alive year-round.

What makes it worth it?

Very few places left on earth deliver the feeling that you have stepped off the map entirely — Odzala does it within an hour of landing. Guests routinely describe the first gorilla encounter as the single most humbling moment of their travelling lives: the silverback's gaze, the infants tumbling in the vines, the total absence of fences, roads or other tourists. 'I've been on thirty safaris and this was the only one that genuinely frightened and moved me,' is a sentiment repeated again and again. Wading waist-deep through a bai at dusk while forest elephants trumpet somewhere behind the palms rewires your idea of what wilderness means. Years later, what stays with you isn't a photograph but a sound — the eerie ringing whistle of a tree hyrax at 2am, or the crack of a branch that tells you something enormous is very close, and you are, for once, not in charge.

How accessible is it?

This is a genuine expedition and priced accordingly: multi-night packages through the park's camp operator generally run from around USD $1,000–1,500 per person per night, with typical 5–7 night itineraries landing between $7,000 and $13,000 including charter flights from Brazzaville, guiding, gorilla tracking permits and all meals. A Congolese visa is required for most nationalities and must be arranged in advance, along with proof of yellow fever vaccination; malaria prophylaxis is essential and comprehensive medical evacuation insurance is strongly recommended. Physically, gorilla tracking is moderate to challenging — expect two to five hours of humid, off-trail walking through dense undergrowth, mud and steep drainages, sometimes twice a day. Groups are strictly limited (usually four to six trekkers), children under a certain age are generally not permitted on treks, and the park hosts only a few hundred visitors annually, so booking six to twelve months ahead is wise. Pack lightweight long sleeves, gaiters, gardening-style gloves for grabbing thorny vines, quick-dry footwear for bai wading and a good rain shell — the Congo will soak you either way.