Examples of ineffective cave gates: 1 - Parts of the gate of the Bratanovata Cave are twisted to allow easier access. 2. The fence at the Divdyadovski Zandan Cave cannot stop visitors. 3 - Access to the Derventskata Cave is officially restricted, but cavers are freely passing through the gate. 4 - Kaleto Cave has a locked gate, but cavers have created a shortcut under it. 5 and 6 - the Elenina dupka Cave has a very strong gate, but cavers have unscrewed the bolts holding the padlock. Photo credits: S. Deleva (1, 2, 4 and 6), M. Kolev (3), S. Markova (5).