We take the idea of sturdy buildings and city infrastructure for granted in the modern era. But as you’ll see on National Geographic’s new show Origins (Mondays, 9/8 CST), since ancient times, innovations in architecture have helped move society forward in ways we don’t always appreciate. Here are seven ways clever architecture and urban design have helped humanity flourish:

1. ROOFS COULD HAVE MADE HUMANS HAIRLESS

One hypothesis suggests that human nakedness may have evolved because better nests rendered warm fur unnecessary. Being furless is great when you’re running in the sun, but once the sun goes down and temperatures drop, fur comes in handy. Figuring out how to build a nest with a roof—i.e., a hut—could have made it more feasible for humans to live without body hair and still stay warm, as one pair of researchers postulates. Unfortunately, as the two researchers who put forth this idea concede, it’s hard to know for sure since those nests would have decayed before making it into the fossil record.

2. URBANIZATION MADE TRADE SPECIALIZATION POSSIBLE …

When people began to concentrate their dwellings in larger groupings, they no longer had to be entirely self-sufficient. People could go to the market and trade for things they couldn’t make or grow themselves, so that a farmer could swap grain for milk and a herdsman could swap wool for new clay pots. But without this critical mass of residents living in one place, you couldn’t eke out a living by just making clay pots or just raising goats—you would need to grow your own wheat and vegetables, make your own clothes, and do everything else you need to survive by yourself.

3. … AND CREATED CIVILIZATION AS WE KNOW IT

The world’s first known cities, like Mesopotamia’s Uruk, reached populations of approximately 50,000 people around 2000 BCE. The concentration of populations in cities, scholars argue, created the conditions necessary for humanity to develop central government, organized religion, civil engineering, writing and art, law, and mathematics. Without cities, in other words, we wouldn’t have invented basic concepts like numbers and weight measurements.

4. CITY SQUARES INCUBATED DEMOCRACY

City-building has centered around large public squares for thousands of years. The ancient Greeks had the agora; the ancient Romans had the forum. These public spaces made it possible to gather crowds of people together for religious ceremonies, public meetings, and more. In medieval Europe, the central market square came to dominate city design. Many scholars now credit these spaces as a vital driver of democracy. Squares are where, before television and the Internet, people went to hear political speeches and debate issues; they’re where people can gather to protest and make themselves heard. Having a single, publicly visible place for political life to take place helped to create the necessary conditions for a democratic society.

5. SECURE BUILDINGS CREATED BANKING

In the ancient world, the rich didn’t want to risk keeping their valuables at home, since those spaces weren’t considered secure. So slightly-more-secure temples became banks as well as places of worship; wealthy people would store currency in the basements of their local temples. In ancient Egypt, the construction of state warehouses large enough to hold grain produced by the country’s farmers led to a centralized way to pay debts. Farmers would deposit their grain (whether for safety or because it was required by the government) and from there, they could withdraw their crops, minus the taxes they owed to the king. Depositing and withdrawing crops from these warehouses became a more general way of trading and paying people.

6. GOOD HOUSING DESIGN MADE HEAT BEARABLE

Before heating and air conditioning, people still lived in extreme climates. Good design helped make it bearable. In ancient India, stepwells basically created basement air conditioning. Pools of water located underneath buildings cooled the structures above through evaporation, creating a much milder microclimate inside the building on even the hottest days. “Windcatcher” towers ventilated buildings in ancient Persia. These tall towers, like reverse chimneys, drew hot air up and out of the house. When combined with the cold air trapped in a qanat (an underwater irrigation system), they functioned as a passive air conditioning system, making even the hottest deserts at least a little more bearable.

7. CHIMNEYS IMPROVED INDOOR AIR QUALITY

Chimneys that funneled smoke from fires away from the building’s inhabitants weren’t common until well into medieval times. But homes were heated by fires, meaning that winters were very, very smoky. Studies reconstructing the environments of houses from the 9th century have found that indoor air quality in the winter would have been pretty unhealthy. When modern study participants were subject to similar conditions, their lung function declined and they were exposed to carbon monoxide on a daily basis, both of which would have had long-term health impacts. Widespread chimney usage would have significantly increased indoor air quality and by extension, improved public health.

From communication to medicine to war and more, National Geographic’s new series Origins rewinds all the way back to the beginning and traces the innovations that made us modern. New episodes, Mondays at 9/8 CST.

Learn more at NatGeoTV.com/Origins.