İnsuyu Cave (Turkish: İnsuyu Mağarası) is a show cave situated near Burdur in southwestern Turkey. Being over 500 m (1,600 ft) in length, it was discovered in 1952 and opened to public in 1965. A second cave beyond the show cave was later discovered. The lakes inside the both caves are in danger of drying due to excessive drilling of wells in the valley above. However, efforts are underway to reverse the process.