For good luck in Barcelona, go to La Casa de l’Ardiaca and touch this turtle.
If you look closely you'll see this is really a letterbox. The birds symbolize the hope that you'll get your mail soon, but the turtle is a nod to the reality of how slow the mail system really is.
This letterbox was designed by modernist architect Lluis Domenech i Montaner in 1902. Barcelona is full of stories and legends that have turned into fun traditions for tourists and locals too.