An apparatus and methods are disclosed for authenticating users of wireless telecommunications terminals. A user is authenticated by instructing the user to travel to a geo-location, where the geo-location is referred to by an identifier that the user has previously associated with the geo-location. When the user chooses identifiers that are meaningful to the user, but that do not indicate the associated geo-locations to other people, the user can be securely authenticated via the following procedure: (i) select one of the identifiers that the user has defined, (ii) instruct the user to “go to ,” and (iii) declare the user authenticated if and only if the user visits the geo-location associated with before a timeout expires.