Situated near the Altaussee about 6km north of Bad Aussee, this working salt mine was the secret hiding place for art treasures stolen by the Nazis during WWII. All tours are bilingual (in German and English). See the website for further opening times. Bus 955 (€2.40, 15 minutes) runs a few times each day from the Bad Aussee post office to the stop 'Altaussee Scheiben', 2.5km from the mine (though bike is a better option as the bus is infrequent).
Tours include the treasure chambers, an underground lake, and a chapel dedicated to St Barbara, the patron saint of miners, which is constructed in the salt.