Cañas y tapas are a must on any visit to Madrid! Madrid is full of cervecerias, small bars where cañas y tapas are served. You order a cañas (beer) and get free tapas with it. The tapas can vary greatly depending on the cerveceria. You simply throw your trash (serviettes, toothpicks etc.) onto the floor. To tell whether a cerveceria is good and popular, check out the amount of trash on the floor. The more trash on the floor, the better the bar. The districts of Chueca and Malasaña are full of such bars.
Chueca and Malasaña