Huge, lush, and kept hush-hush by the local shipping families, Andros is only two hours by ferry from Athens. The main town, with its neoclassical mansions, fine-art museums, and yacht club, is more Downton Abbey than Aegean village. The mountainous interior is another world—all rushing streams and springs, waterfalls and wetlands, with 84 villages hidden in the valleys and forests. This unexpected wonderland is now accessible thanks to Andros Routes, a grassroots initiative to clear and waymark the 186 miles of ancient footpaths that crisscross the island. To date, volunteers have opened up 20 paths, including the Andros Trail, a continuous 62-mile path that straddles the whole island.