"Free internet in Oporto" by Fra Biancoshock.

Were detected 53 locations in the city center and neighboring areas where internet connection is offered by people who didn't care to put a password to their account. In this way everyone can connect to the internet for free at the point indicated by the sign and may even know the nickname of the user who is giving internet and, at that time, will have a connection to internet line much slower. Signs are 53 "thanks!" to 53 people who "decide" to have a slower connection to allow especially tourists (who otherwise would pay their telephone company to get internet in another state) to connect their smartphone for free.

Source: Fra Biancoshock