These are the most developed worlds, nearly entirely urban in landscape with a high level of technology. Electricity is abundant and nuclear energy is often used. Currently only the Capitol world is an example of this, but a nearby world specializing in shipbuilding and technological commerce is coming close to this state.
Typically only the upper-class live here. Machinery is built to do much of the manual labor, especially in factories where goods are refined. These worlds have a much more science-fiction feel. Typically food is brought in from off-world. However nearly every household has a large fishtank that is a self-sustaining system; the fish are edible, and waste from the fish feeds freshwater lettuce that grow hydroponically in the same tank. This and nutritive algae are common staples of the diet. Algae in perticular is thought of as a love-it-or-hate-it breakfast food (similar to natto).
Culturally, the Capitol is the center of political clout. Representatives from colonies are elected to lifelong terms but are ultimately outnumbered by representatives from the Capitol itself. Cultural influences from the Capitol also trickle down to the colonies, though somewhat slowly.