ConstructionA ruler may choose to build more than one item at a time but be aware that each city-state has only one construction facility at its disposal. This one construction facility will be in charge of all items being built. This means construction will take longer if more items are being built at the same time. However, if in a hurry, there's a speed-up option available.

The Constructor facility generates an amount of construction points every minute, amount that can be improved via research or effects.

When it comes to Industries and Special Facilities, you also need to make sure you've already researched the corresponding Industry Upgrade or Improvement tech.