COLLAPSIBLE ENTRANCE DOOR

An apparatus includes a first portion of a collapsible door and a second portion of the collapsible door. The second portion of the collapsible door is slidably coupled to the first portion such that the first portion is configured to slide vertically relative to the second portion to move the collapsible door between a collapsed configuration and an expanded configuration. The first portion and the second portion collectively are configured to pivot about a single hinge axis to move the collapsible door between an open position and a closed position in both the collapsed configuration and the expanded configuration.