Not long ago the sleepy village of Phong Nha barely got a mention in guidebooks, but the surprise discovery of one of the world’s largest caves has catapulted it into the international adventure tourism spotlight. The Phong Nha-Kẻ Bàng National Park is a rugged swathe of limestone mountains containing a multitude of vast caves inside. It’s also home to endangered wildlife, magnificent evergreen trees, endless grottos and friendly ethnic minority groups. The gateway to this land of adventure is Phong Nha, a welcoming village on the banks of the graceful Son River.