From RIPO:

“Si Ves Algo Di Algo” (If You See Something Say Something) is the phrase made infamous by the NYC transit authority, aka the MTA. To the MTA that means spy on your neighbor and report everything and anyone you suspect may be a terrorist or a threat to the security of the norm. I prefer to see the meaning of that phrase as a reminder to us to keep our eyes open and react to and interact with our evironments in positive ways. Taking back a sinister and Big Brother-esque phrase and turning it into something that speaks to people as a positive thing rather than a negative.

Freedom of Public Space, Freedom for our Eyes. Painted in the Gracia neighborhood in Barcelona, Spain.