There&#x27;s a lot more in the German version of the article, including a second possibility of what they were used for. A number of reasons is listed why it might make sense to consider them places of refuge in case of an attack:<p>- entrances are generally hidden<p>- narrow slip holes make defense simple<p>- locking mechanisms that can only be operated from the inside were found<p>- some are directly connected to fortifications<p>But it would also be excessively easy for an attacker to just kill the inhabitants by sealing the entry &#x2F; smoking them out if they were found. They&#x27;re also rather unsuitable for prolonged hiding (little space = little air, need to bring food, no way of getting rid of faeces other than burying them), but 48h have been experimentally confirmed as possible for 3 adults.