Mah god. I thought it was a picture of the sign saying CA4, and that that was some clever joke for some reason that was beyond me. Focusing on the wrong part of the picture I guess.
I my search to understand the joke I googled CA4 and everything. Turns out CA4 is the Central-America-4 border agreement which, much like the schengen area in Europe, allows for free movement between the central American nations of El Salvador, Guatemala, Honduras and Nicaragua.
It could also be Carbonic andryhase 4 (CA4), a large family of zinc metalloenzymes that catalyse(speed up, or lower the amount of energy needed to start the reaction, or both!

) the reversible hydration of carbon dioxide (CO2). Though I figured that probably wasn't the joke.
Then I searched for Cafor (see, CA four = cafor) which brought results of a high school in Cali, Columbia, or
a spanish website which provides education about 'el trabajo yel desarollo humano'.
I thought though, that this joke had nothing to do with Spanish websites or latin american high schools. So I searched on!
For cafour, which only brought me
Carrefour, a chain of french supermarchés, or hypermarchés according to themselves. Apperently you can also shop online and they will bring it to your house

.
Anyway, that's when I gave up.