Sprawling across almost 300,000 hectares, PNN Amacayacu is an ideal spot from which to observe the Amazonian rainforest up close. About 75km upriver from Leticia, the park is home to 500 species of birds and 150 mammals and dozens of reptiles including crocs, boas and anacondas. And millions of mosquitoes. Activities include bird-watching, kayaking and multiday hikes.