Right, this is the OVH “tower” data center design. Here’s a google maps link to the OVH Strasbourg site https://goo.gl/maps/rQjir8byKNwMDZrm9 with (from south to north) SBG1 (a collection of shipping containers), SBG2 (a figure 8 shape), and SBG3 (a box).

The idea of the tower design is to take ambient air in through the outside walls, through I think just one row of servers, then into a central void where convection pulls the air out.