A multi-floor data center, comprising in one implementation, a plurality of floors; a first set of server racks disposed about a first vertical center axis on each floor, the first set of server racks formed in a substantially closed shape, with a substantially vertical open center comprising a first airflow plenum at least for air flow; a first opening in each of the floors, with the first opening aligned with the substantially vertical first airflow plenum on it respective floor, wherein the substantially vertical first airflow plenums on the floors are aligned for communication through the first openings in the floors; outer wall; a roof with a roof opening therein.