Map showing the location of Ankarana Special Reserve

Ankarana Special Reserve in northern Madagascar was created in 1956. It is a small, partially vegetated plateau composed of 150-million-year-old middle Jurassic limestone. With an average annual rainfall of about 2,000 millimetres (79 in),^[1] the underlying rocks are susceptible to erosion, thereby producing caves and underground rivers—a karst topography. The rugged relief and the dense vegetation have helped protect the region from human intrusion.

• http://en.wikipedia.org/wiki/Ankarana National Park