We leave Cusco (3,400 m / 11,155 ft) early in the morning and head for the cloud forest, where the Andes fall away to the Amazon basin. On the way, we visit a high mountain wetland with migrant and local waterfowl and cross two mountain ranges between the Cusco and Paucartambo valleys, reaching a maximum altitude of 3,900 m / 12,795 ft. We stop at mountain villages and at the pre-Inca burial towers (chullpas) of Ninamarca. At the Ajanaco pass, the entrance to Manu National Park, the Andes begin their plunge into the Amazon basin – in clear weather, the view over the cloud forest down to the lowland rainforest is breathtaking. After lunch, we descend through elfin forest into a magical world of giant ferns, orchids, bromeliads and begonias. With frequent stops, we may spot quetzals, trogons or guans before reaching the Cock-of-the-Rock Lodge in the afternoon.

Early in the morning, we look for birds and perhaps woolly or brown capuchin monkeys near the lodge. After breakfast, we drive on as the mountains give way to low hills and farmland, and visit a coca plantation in Patria that grows leaves legally for the Peruvian market. At midday, we reach the tiny port of Atalaya, where the lowland part of our journey begins: from now on, we travel in large, roofed motorized canoes. Along the Alto Madre de Dios, we see terns, cormorants, white-winged swallows and flocks of nighthawks. We then turn north up the chocolate-brown Manu River into the national park, register at the Limonal ranger station and continue to Romero Lodge, where the sounds of the rainforest accompany us into the night.

In the morning, we continue up the Manu River. Orinoco geese and horned screamers stroll on the beaches, herons patrol the shore and sunbathing turtles slide off their logs as we pass. After about four hours, we reach Casa Matsiguenka, a simple, comfortable lodge run by the indigenous Matsiguenka communities of Tayakome and Yomibato. Time permitting, we take a short walk before dinner – our first encounter with the virgin rainforest.

Today we visit two oxbow lakes, formed when the river changed its course. The park authorities set the time of our visit to Cocha Salvador; depending on this, we visit Cocha Otorongo earlier or later in the day. On the way, we may spot capybaras on the riverbank or, with great luck, a jaguar. At Cocha Otorongo, a dock and a 15 m (50 ft) observation tower let us scan the shores for monkeys, kingfishers, hoatzins, anhingas and the resident family of giant otters. Cocha Salvador, the largest lake of the area at 3.5 km (2.2 mi), is explored on a floating catamaran: monkeys in the trees, macaws overhead, herons and egrets on the shore, caimans in the shallows – and, with luck, the shy giant otters fishing and playing together.

We set off downriver at dawn, when the chances of wildlife encounters are best, and leave the park at the Limonal ranger station. Past the village of Boca Manu, we continue for another ninety minutes downstream and reach the Manu Wildlife Center in time for lunch. In the afternoon, our guide leads us on the lodge's trails in search of monkeys and many species of birds, and those with energy can climb the canopy observation tower. In the evening, if the river level allows, we go out by boat to look for caimans and other nocturnal animals.

After an early start and a short boat ride, a 20-minute trail leads to the Blanquillo macaw clay lick. From a comfortable hide, we enjoy breakfast while red-and-green macaws and blue-headed, mealy, yellow-crowned and orange-cheeked parrots gather in the treetops and finally descend in a colorful, noisy spectacle to eat the clay. The lick is most active from August to October and less so in May and June. After lunch, we explore the trails and then walk to the famous tapir clay lick, the most active known in the Amazon. From a raised, padded platform with mattresses and mosquito nets, we wait – sometimes for hours – for the tapirs, the largest land animals of South America, to come out of the forest to eat clay just 10–20 m (33–66 ft) away. Flash photography is allowed.

We leave the lodge very early for a boat trip of about two and a half hours downstream to the gold-mining town of Colorado; breakfast is served at the lodge or on the boat. On the way, we see lowland settlements and gold miners along the Madre de Dios River. From Colorado, we drive about 45 minutes to Puerto Carlos, cross the Inambari River by boat to Santa Rosa and continue by van for about two and a half hours to the airport of Puerto Maldonado, from where you fly to Cusco or Lima.