A method for retrieving content stored in a warehouse, the method may include: maintaining first content in boxes of a lowest shelf of a storage unit of the warehouse, while maintaining in boxes of higher shelves of the storage unit second content that is of less interest than the first content; accessing the boxes of the lowest shelf and providing the boxes to interfacing units, by a first robot; accessing the boxes of the higher shelves and providing the boxes to the interfacing units, by a second robot; wherein the first robot, when positioned at a lower position, is lower than a height of the lowest shelf; and wherein the second robot is higher than the height of the lowest shelf.