"Out of all the cabins, eleven looked the most like a regular old summer camp cabin, with the emphasis on old. The threshold was worn down, the brown paint peeling. Over the dorrway was one of those doctor's symbols, a winged pole with two snakes wrapped around it. What did they call it . . . ? A caduceus.
Inside, it was packed with people, both boys and girls, way more than the number of bunk beds. Sleeping bags were spread all over on the floor. It looked like a gym where the Red Cross had set up an evacuation center."
~The Lightning Thief


This is where demigod children of Hermes stay, along with the unclaimed campers.