The Periyar Wildlife Sanctuary at Thekkady is one of India's finest, covering 777 sq km of tropical forest in the Cardamom Hills. The drive there is part of the appeal, winding through tranquil countryside, spice plantations and thick jungle.
The sanctuary is centred on an artificial lake, and the standard way to see the wildlife is on a boat cruise across it. Elephants, gaur (Indian bison), sambar deer and wild boar come down to the water's edge to drink, and if you are patient you may spot them from the boat. The birdlife is excellent too, with Malabar grey hornbills, grey jungle fowl and many others. For a more immersive experience, the forest department organises guided treks, bamboo rafting trips and overnight camps with trained tribal guides.
The town of Kumily, just outside the sanctuary entrance, is the base for most visitors. The surrounding hills are covered in tea, coffee, cardamom and pepper plantations, and you can arrange spice garden tours from here.