The Bio-Domes used by the Department of Aristocratic Research are giant regulated envireoments, in which Archibald Sodium runs his kingdoms.
The seven Domes each contain one simulation of a historical time period's cultures, in the case of most, medieval times, though the level of technological advancement is known to be highly advanced despite this. Thanks to a small amount of reality warping, they each contain a far larger space than they should be physically able.
The Domes are policed by Archie's private military, and located, along with the rest of the Department, in a separated sector, accessible only by a short train commute.
Recently, the Domes have been annexed together under the rule of Archibald's latest nation, Cheria, which is an entire continent located in a pocket dimension, accessible through several points.