A closing arrangement for closing an opening that is formed between a first closing portion and a second closing portion, wherein the closing arrangement includes a first closing part and a third closing part for arrangement on the first closing portion and a second closing part for arrangement on the second closing portion, wherein - the first closing part has a first strip body longitudinally extended along a transverse direction (x), - the second closing part has a second strip body longitudinally extended along the transverse direction (x), - the first closing part and the second closing part cooperate in a magnetically attracting manner in such a way that in a closed position of the closure device the first closing portion and the second closing portion rest against each other and form a closure compound with the first and second closing parts (21, 20), - the closure compound can be adjusted from a release position, in which the first and second closing portions (104, 105) can be properly separated from each other against a magnetic force applied by the first and second closing parts (21, 20) to clear the opening, into a closing position in which the closure compound and the third closing part cooperate in a magnetically attracting manner in such a way that the closure compound is maintained in the closing position, - the closing arrangement comprises an additional securing mechanism via which the closure compound disposed in its closing position is additionally secured against removal from the third closing part and hence against undesired opening in the closing position, and - the closing arrangement is provided for closing an opening via which a hollow body is accessible, which is bordered by at least one flexible wall (100, 101) characterized in that the securing mechanism is adapted to counteract a removal of the closure compound from the closing position due to an increased internal pressure in the hollow body, and the first and second strip bodies (212, 202) have two longitudinal ends and, in the closing position, the securing mechanism is adapted to - counteract a lifting force acting on the first and second strip bodies (212, 202) at the longitudinal ends and resulting from the increased internal pressure, by action of which mutually opposite longitudinal ends of the first and second strip bodies (212, 202) strive to move away from each other, and/or - counteract a shear force resulting from the increased internal pressure, which acts in a middle area of the first or second strip bodies (212, 202) on the closing arrangement in a plane (xz-plane) extending parallel to the first and second closing portions (104, 105). - the first closing part has a first strip body longitudinally extended along a transverse direction (x), - the second closing part has a second strip body longitudinally extended along the transverse direction (x), - the first closing part and the second closing part cooperate in a magnetically attracting manner in such a way that in a closed position of the closure device the first closing portion and the second closing portion rest against each other and form a closure compound with the first and second closing parts (21, 20), - the closure compound can be adjusted from a release position, in which the first and second closing portions (104, 105) can be properly separated from each other against a magnetic force applied by the first and second closing parts (21, 20) to clear the opening, into a closing position in which the closure compound and the third closing part cooperate in a magnetically attracting manner in such a way that the closure compound is maintained in the closing position, - the closing arrangement comprises an additional securing mechanism via which the closure compound disposed in its closing position is additionally secured against removal from the third closing part and hence against undesired opening in the closing position, and - the closing arrangement is provided for closing an opening via which a hollow body is accessible, which is bordered by at least one flexible wall (100, 101) the securing mechanism is adapted to counteract a removal of the closure compound from the closing position due to an increased internal pressure in the hollow body, and the first and second strip bodies (212, 202) have two longitudinal ends and, in the closing position, the securing mechanism is adapted to - counteract a lifting force acting on the first and second strip bodies (212, 202) at the longitudinal ends and resulting from the increased internal pressure, by action of which mutually opposite longitudinal ends of the first and second strip bodies (212, 202) strive to move away from each other, and/or - counteract a shear force resulting from the increased internal pressure, which acts in a middle area of the first or second strip bodies (212, 202) on the closing arrangement in a plane (xz-plane) extending parallel to the first and second closing portions (104, 105). - counteract a lifting force acting on the first and second strip bodies (212, 202) at the longitudinal ends and resulting from the increased internal pressure, by action of which mutually opposite longitudinal ends of the first and second strip bodies (212, 202) strive to move away from each other, and/or - counteract a shear force resulting from the increased internal pressure, which acts in a middle area of the first or second strip bodies (212, 202) on the closing arrangement in a plane (xz-plane) extending parallel to the first and second closing portions (104, 105).