The biodiversity of Madagascar is staggering: It’s home to more than 11,000 plant species, and close to 90 percent of the wildlife in this African island nation can be found nowhere else. Even the top eco-lodges here were rough around the edges until the arrival of Miavana, a private island resort off the northeastern coast. Miavana is undeniably over-the-top (the sustainably designed villas start at nearly 5,000 square feet), but the wildlife encounters are the real draw. Along with snorkeling and marine safaris, the resort offers guided treks to see native species such as jeweled chameleons and silky sifaka.