Basically, it's a street where they painted the road pink. Half of it's one side of an underpass and the other half is the other side of it. The area is not particularly salubrious, and most people would probably be more inclined to avoid it rather than to visit it. However, by painting the road pink it was transformed into a tourist attraction. Tourists (such as me) are duly attracted to it.
I thought it was called Pink Street because it was full of gay bars or something. It may well be, come to that, but the actual reason for the name is that it was the heart of the old red light district which isn't so red any more. Look it up if you don't believe me.
Its actual name is Rua Nova do Carvalho, or "New Oak Street". I don't know if the "Oak" part is some kind of nudge-nudge, wink-wink euphamism in Portuguese, but if not then it ought to be.
Using Pink Street logic, I think the runways at Heathrow Airport should be painted a pale yellow, maybe cream, on the grounds that they used to be wheatfields.