The cave was first opened in 1949, when a hydraulic blowup removed a rock and caused a huge flood in the Fundata valley. In 1954, a group of young from Râşnov managed to enter the cave through the opening. Margareta Dumitrescu and Traian Orghidan conducted the first study of the cave complex in 1958 and published a description and a sketch of the cave, indicating its length of 270 m. In 1981, a team from "Emil Racoviţă" speleological club in Bucharest have mapped 857 m with a 36m level difference. In 1988 and 1989 were mapped another 63 m, respectively 38 m, with a level difference of 38.5 m and a development of 958 m. The cave has undergone a continuous process of destruction due to uncontrolled access to various visitors.
Since February 2010, the protected natural area of the Fortress Valley Cave is in the custody of a firm. From this time, the damage of the karstic formations was fortunately stopped, and the cave was set up using the latest technology. The cave was opened for visiting by the public in December 2010 after a titanic work of restoration. Due to the amazing acoustic of the cave, it used also for classical music concerts.
Photos from here