'Wow' took charge of the making of fibreglass of the giant shoe, 4.5m x 1.5m in size, a very dirty shoe bearing the typical message that people scrawl with their finger on dirty cars: 'Please, clean me!' In addition, it sought out typical locations for cars in which to place the shoe, establishing a circuit over several months in the cities of Madrid and Barcelona: shopping centre car parks, tow-away trucks driving through the city, pedestals in airports displaying new models of cars, parked in the street in the midst of a line of cars ...