Lumea Pierdută is a forested karst plateau, bounded by Prâul Ursului, Prâul Sec and Vârful Gârdișoara. The isolated plateau includes two valleys, Bear Stream and Sec Stream, which have their sources nearby and join downstream.
Beneath the plateau there is a vast network of underground galleries, suggested on the surface by sinkholes covered with vegetation. Two avenues, Avenul Negru and Avenul Gemănata, provide access to this network. Avenul Negru has a vertical of 79 m, and Avenul Gemănata has a vertical of 64 m, divided by a natural bridge.
The underground network drains water from Prâul Sec along a 2,700 m route to Izvorul Rece. Prâul Ursului is fed by springs on Mount Gârdișoara, and its waters, along with those of Prâului Sec, are collected in the Căput Cave, which drains to the underground gallery of the Ponorului Cetătări.
Sursa: parcapuseni.ro
