Doi Chiang Dao rises dramatically above the surrounding plain, wrapped in a thick coat of tropical forest. This jungle wonderland is one of Thailand's top spots for birders, with more than 300 resident species, and is one of the best places in the world to see giant nuthatches and Hume's pheasants. It's a steep full-day hike to the summit, which offers spectacular views over the surrounding massifs; a one-day trip is 1000B per person, overnight costs 500B per person.
If you just want a taste of the marvellous scenery, take a right at the junction just before the cluster of lodges at Ban Tham and follow the gorgeously scenic, winding mountain road that climbs to the ridge through the forest. This is a challenging route and you'll need transport with sufficient power to handle the gradients.