1. A modular warehouse system comprising: at least two modular stackable bins wherein said bins does not require structural support and may allow retrieval of at least one of said bins, regardless of its location in the pile, without changing said pile's order; at least two bin retrieval robots; at least one non-transitory computer-readable medium storing processor executable instructions on a computing device for warehouse management, adapted to: manage said warehouse inventory; manage said at least two bin retrieval robots and said at least two cars' traffic; and allow user to simulate scenarios related to said warehouse system and present said simulations results to said user via a user interface; wherein said modular warehouse does not require shelving.