The Grand Boucle is the longest of the day hikes signposted from the airstrip — a roughly 20 km loop through old-growth rainforest on the slopes of Mont La Fumée. It is the standard "serious day" for fit walkers and the best chance of seeing larger mammals on a single trip: groups of red howler monkeys, occasional tapir tracks in mud, and trails of leafcutter ants metres wide.
Plan eight to ten hours including breaks. The path is marked with painted strips on tree trunks but those marks are easy to miss in low light or rain. Most visitors take a local guide for this route; the village association keeps a list. Carry at least three litres of water per person, a head torch in case of late return, and waterproofs even in dry season.