If you've ever traveled the nation's highways on a road trip, you've probably had a lot of fun seeing the names of new cities as you come upon them. Many cities greet you with a large “Welcome!" sign that might also include interesting information, such as the city's motto and the year it was founded.

Several of our Wonder Friends have been WONDERing about how exactly cities get founded. So we decided to investigate and share what we learned!

Some cities have only been around a few years. (Yes! New cities are still being founded today!) Other cities may have been around for tens, hundreds, and even thousands of years.

Historians believe the first cities came into existence between 8,000-10,000 years ago. Some scientists believe the very first cities were founded around 7,500 B.C. in Mesopotamia. Some of the first cities included Eridu, Uruk, and Ur. Around this time, other cities sprang up in the Indus Valley (modern Pakistan) and ancient China.

People were mainly nomadic hunters and gatherers before these first cities were founded. The development of agriculture and the domestication of animals, however, allowed people to stop roaming and settle in one place. The creation of cities allowed people to store surplus food production and minimize the transport costs for goods and services.

Along with the development of agriculture, societies began to become more complex. People developed new systems of writing. Technological advances, such as the plow, potter's wheel, loom, and metallurgy, also helped draw people to cities where goods and services could be bartered.

As time marched on, more and more cities were founded around the world. Not all cities were created for the same reasons. For example, some cities grew up around intersections of ancient trade routes. Rather than a center of agriculture or manufacturing, these cities were large marketplaces focused on trade. Such cities often formed where goods would move from one mode of transportation to another, such as at a river or ocean port.

Before the invention of modern warfare techniques, many cities were founded for defensive purposes. Walled cities were common in ancient history, when walls could protect a city from an attack. The invention of modern heavy artillery and aerial warfare rendered the protection of walled cities mainly useless.

As populations grew, cities also became important centers of government. While they might also serve other functions already described, certain cities arose as seats of power for centralized government of a state or nation. Washington, D.C., is an example of such a city in the United States.

As you can see, cities perform many important functions and can be founded for a variety of reasons. To found a city, pioneers faced many obstacles. Favorable land had to be found that suited the purposes the founder had in mind. Good sources of water and land to grow food were usually at the top of the list. Depending upon the goals of the city, other considerations might also be important, such as access to trade routes.

Today, we don't really hear that much about new cities being founded, but guess what? It still happens! Most new cities today come into existence when rural or suburban unincorporated areas decide to incorporate as a city.

Why would they do this? Again, the reasons can vary by region and purpose. Some may incorporate to control their own destiny rather than be controlled by another local city or governmental entity, such as a county government. Still others may do so in order to provide necessary benefits to citizens, such as police or fire protection.

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