I thought this was a cool sign - simple and straight to the point with some humor in it.
It was built in the 1930's to take dangerous freight traffic out of the city's main industrial areas. The line had not been in use since the 1980's and in 1999 a non profit group save it from being demolished and proposed to turn it into a park.
Since then the local goverment and the Friends of the High Line have worked to turn this space into a park for the enjoyment of New Yorkers and tourists alike. The first section of the park opened in 2009 and the second part, which in currently under construction, it scheduled to open in 2011.
I love the design done by landscape architects James Corner Field Operations, with architects Diller Scofidio + Renfro. The whole concept is environmentally friendly and modern adapting the whole space to the surrounding buidlings providing a beautiful landscape to hotels and office buildings alike.