Steep limestone cliffs and forested hills edge the lower Macal River, whose main tributaries rise in the Mountain Pine Ridge Forest Reserve and the Chiquibul Forest. In the upper reaches the water is sometimes suitable for whitewater kayaking, though you’ll need a guide for this. A guided canoe trip, however, is by far the best way to visit one of the river’s top sights, the Rainforest Medicine Trail (daily 8am–5pm), in the grounds of The Lodge at Chaa Creek, 5km upriver from San Ignacio. The medical knowledge of the Maya was extensive, and the trail, dedicated to a Maya bush doctor (curandero), is fascinating: among the plants here you’ll see the negrito tree, whose bark was once sold in Europe for its weight in gold as a cure for dysentery. The Chaa Creek Natural History Centre, next to the Medicine Trail (daily 8am–5pm), offers a marvellous introduction to Cayo’s history, geography and wildlife. A combined ticket for both the above is Bz$20. At du Plooy’s resort, a few kilometres upstream from Chaa Creek, the ambitious Belize Botanic Gardens (daily 7am–5pm; Bz$20; t 824-3101, w www.belizebotanic.org) aim to conserve many of Belize’s native plant species in small areas representative of their habitats.