This article is under construction. Please excuse the mess.
The Provisional Diplomatic Cylinder, generally referred to as the Sill, is a city on Counterweight. Unusually for cities on Counterweight, it is a long climate-controlled cylinder instead of a dome, with a (relatively) low, transparent ceiling. The CCT officially directs the Sill, while much real power is in the hands of the Apostolosian Ithikos crime family, who run the central casino known as the Cerulean. It mainly relies on tourism and entertainment. Entrance to the Sill is highly monitored between the oversight of the CCT and the Tourist's Union.
The Sill was built long pre-war in attempt to build diplomacy between Apostolos and its new rivals in the Diaspora and OriCon. Hopes for it to become the center of governance on Counterweight failed to pan out.
Toxic dust from outside will occasionally break the Sill's air filters, lowering temperatures and making ash that looks like snow fall inside the cylinder.
The Sill's eastern gate is now the only entrance. The residential areas cluster around the east side, with the agora, embassy district and Cerulean casino following as one moves west. The far western end has been taken over by the Open Arms campground.
Agora
The Sill's agora is a large park and open marketplace, even larger than the Cerulean. It also houses Apostolosian temples.
Cerulean
The Cerulean was originally built to be the center of a unified government of Counterweight. It was taken over by the Ithikos and turned into a casino which sprawls out into surrounding buildings in a way reminiscent of the UN headquarters. It is painted a bright, gaudy blue.