1. A door barricade for a door having an interior face and an exterior face, the door barricade designed for use on the interior face and locking in an adjacent floor comprising:a) a door interior face flat mounting plate, the mounting plate consisting of an exterior face and an interior face designed for vertically mounting the interior face of the mounting plate against the interior face of the door of a material designed to help prevent access to the barricade from the exterior face of the door and designed such that the flat mounting plate is the only part of the barricade touching the interior face of the door;
b) a straight vertical bolt capable of rotating circumferentially and moving up and down to an upper and lower position of a length that does not reach the floor when the bolt is in a down position attached to the barricade in spaced relationship to the interior face of the door;
c) at least one holding device attached to the mounting plate designed to keep the vertical bolt vertical relative to the mounting plate and allow the vertical bolt to rotate circumferentially and move in an upward and downward manner to the upper and lower position;
d) a single floor device with a receiver hole for attaching to the adjacent floor; and
e) a locking arm fixedly attached to the vertical bolt having a fixedly attached locking foot at the bottom of the locking arm extending below a bottom of the straight vertical bolt, the foot in horizontal fixed spaced relationship to the vertical bolt and capable of locking only into the single adjacent floor receiver hole when the bolt is in the down position.