Doi Inthanon National Park, Chiang Mai One of the Kingdom's most popular, the nature trail at Ang Ka Luang allows you to enjoy the moss- and fern-covered trees in a patch of evergreen forest near the 2,565-metre summit of Doi Inthanon, Thailand's tallest mountain. This high-altitude habitat is also home to many species of animals, including resident and migratory birds that can be spotted during the cool season.