traitor's gate

Fifth principle. Heterotopias always presuppose a system of opening and closing that both isolates them and makes them penetrable. In general, the heterotopic site is not freely accessible like a public place. Either the entry is compulsory, as in the case of entering a barracks or a prison, or else the individual has to submit to rites and purifications. To get in one must have a certain permission and make certain gestures. Moreover, there are even heterotopias that are entirely consecrated to these activities of purification -purification that is partly religious and partly hygienic, such as the hammin of the Moslems, or else purification that appears to be purely hygienic, as in Scandinavian saunas.