If you have spent any time along the High Line Park in Chelsea, you will recognize this extremely prominent billboard that one artist had the audacity to climb and hack away at.
The original message (WTF is alternate side of the street parking anyway?) was selectively deleted to make way for a replacement question.
Working at night, Poster Boy risked discovery by people parking and picking up their cars in the directly adjacent lot, not to mention being highly visible from the street.
During the day, visitors sitting in the over-street theater seats within the elevated park have a direct view of this huge black-on-yellow poster. It is doubtful the change will survive long, so check it out while it lasts!
Known for his creative edits of local signage and hacked infrastructure, Poster Boy has a huge collection of photos you can browse of his work, ranging from small stickers added in unusual contexts to whole-billboard transformations.