> In Europe, we typically mark the ground-floor as floor-zero, _Western_ Europe. Eastern Europe prefers 1-based numbering. The reason, typically assumed, is th

> In Europe, we typically mark the ground-floor as floor-zero, _Western_ Europe. Eastern Europe prefers 1-based numbering. The reason, typically assumed, is that thermal isolation, required due to colder winters, causes at least one stair segment between entrance and the sequentially first floor.