Inventions occur in this game around certain decades. Usually, the inventions listed below will happen within a decade (on both sides) of the date listed for your use.

• Arcologies - 2000/2050/2100/2150
• Buses/Bus Depot - 1920
• Desalinization Plant - 1990
• Fusion Power Plant - 2050
• Gas Power Plant - 1950
• Highways - 1930
• Microwave Power Plant - 2020
• Nuclear Power Plant - 1955
• Solar Power Plant - 1990
• Subway System - 1910
• Water Treatment Plant - 1935
• Wind Power Plant - 1980