10 traits tracked
Independent convergence
Some inventions spread by contact. Others were arrived at separately, by civilizations with no documented link to each other. Each page below ranks every civilization with a given trait by when they adopted it, and flags which adoptions can plausibly be called independent.
Monumental architecture
Large-scale public construction — pyramids, temples, palace complexes — requiring organized labor beyond a single household.
Irrigation agriculture
Engineered water management — canals, qanats, reservoirs — to extend or stabilize farming.
Long-distance trade
Documented exchange of goods across distances well beyond local markets.
Urban planning
Deliberate, organized city layout — streets, drainage, zoning — rather than organic sprawl.
Standing army
A permanent, professional military maintained outside of wartime levies.
Astronomical record-keeping
Systematic observation and recording of celestial cycles, often tied to calendars.
Bronze metallurgy
Smelting and casting copper-tin alloy tools, weapons, or ornaments.
Iron metallurgy
Smelting and working iron at a scale beyond rare meteoric iron curiosities.
Seafaring
Open-water maritime travel and trade, beyond simple river or coastal craft.
Codified law
A written legal code, as opposed to purely oral or customary law.