Tràng An Scenic Landscape Complex - Credit: Wikimedia Commons
Tràng An is a scenic area near Ninh Bình, Vietnam renowned for its boat cave tours.Lonely Planet Vietnam Lonely Planet, Iain Stewart, Brett Atkinson - 2012 "Boat trips (100,000d for up to four people) take two hours to tour the caves and tunnels. Bring a hat and sunscreen as the boats lack shade. Trang An is 7km northwest of Ninh Binh" Read more on Wikipedia
Source: en.wikipedia.org