The sounds from Bali’s rainforest dominate the senses—birdsongs, the rush of the Ayung River cutting through the valley far below. Trees extend to the horizon. The humid air is momentarily lifted by the breeze that works its way through the thin shade curtains wrapped around the thatch-roofed shelter.
 
Massage tables fill the shelter, which is perched on a ledge overlooking the Indonesian island’s lush, green Ayung Valley. The “Rainforest Retreat,” as it is known, is part of the Alila Hotel,....