This is a scientific American 60 Second Science. I'm Cynthia Graber. Got a minute?

Teotuacan in central Mexico is an archaeological site, a cultural landmark and a tourist attraction best known for its pyramids in Plaza, but nearly 2,000 years ago it was a powerful urban center home to more than 150,000 people.

It was also one of the best planned and most diverse of such pre-industrial

cities because migrants of different ethnicities streamed in following the eruptions of

two volcanoes in southern Mexico that made their own homes less desirable and as

Teotihuahuan grew stronger it attracted additional migrant workforces.

These newcomers tended to serve as crafts people, construction workers, musicians,

and military personnel.

Now researchers have developed methodology to study the remains of one multi-ethnic neighborhood

using paleopathology, nutritional status, and DNA along with other techniques and they found

that migrant groups appear to have competed amongst each other to obtain high status

goods and to manufacture items in demand by the city's elites. The study is in the journal

Proceedings of the National Academy of Sciences. Study author Linda Mancania of

the Universidad National Autonuma de Mexico also points out that the city's

rulers controlled the flow of all raw materials

coming into Teotihuacan. She further suggests that the lower-class immigrants

competition with each other, the intermediate elite gaining economic power, the ruling elite's control over raw materials

may have combined to contribute to the cultural tension that ultimately led to Teo Tewakan's collapse.

Sound familiar? Thanks for the minute.

For Scientific American 60 Second Science, I'm Cynthia Graber.