The Mann Site in Evansville (Indiana, USA) boasts around 20 mounds built by the Hopewell Tradition, a way of life that flourished in the Eastern and Midwestern U.S. nearly 2,000 years ago.
     "What you're seeing here is a complex of earthen structures that were very purposefully and very specifically built along this cultural landscape," says Michele Greenan, an archaeologist and curator at the Indiana State Museum. "There's a number of mounds here - probably 20, maybe even more mounds, earthen architectural features that were built for different purposes," like ceremonies or burial, she says. Two of site's earthen structures are among the biggest mounds built anywhere by the Hopewell.
     An exhibit of artifacts from the Hopewell site, curated by the Indiana State Museum and on display at the Angel Mounds State Historic Site in Evansville, Ind. through January 14, is raising some fresh questions about these ancient Americans. The exhibition is titled Cherished Possessions: The Mann Hopewell Legacy of Indiana.
     Amateur archaeologist Charlie Lacer began walking the Mann fields in the 1950s, collecting what he found along the way: 40,000 artifacts that he donated to the Indiana State Museum two years ago. Four hundred of those pieces are now on display in nearby Evansville for the first time ever.
     Clay figurines discovered on the Mann Hopewell Site show faces with slanted eyes, which were not a Hopewell feature. Some believe the figurines show a connection between Indiana and Central or South America. The discovery of incisor teeth from grizzly bears, which are not native to Indiana, shows that Hopewell residents of the Mann Site had contact with the North American West, where grizzly bears are more common. Jaguars and panthers aren't from Indiana, either, but they show up at the Mann Hopewell Site as beautifully detailed carvings.
     The Mann Hopewell Site is bigger than its more famous Hopewell counterparts in Ohio, and it's filled with even more exotic materials, like obsidian glass that has been traced to the Yellowstone Valley in Wyoming, says Mike Linderman, who manages state historic sites in western Indiana. "There's a theory out there now that instead of being trade items, these items [were] actually being collected by the people from Mann Site on rite-of-passage trips they [were] taking out to the West. You know, it's something big if you've killed a grizzly bear and you can bring its teeth back to Indiana," he added.
     In 2006, researcher Staffan Peterson did the archaeological version of an MRI scan on 100 acres at the site. Whenever his equipment detected an archaeological feature, a dot showed up on a map. "Every day, we'd download our data and our jaws would drop," Peterson says. "It was kind of like buckshot, there were so many. And we were able to map out upwards of 8,000 archaeological features." Two of the most notable features are what Peterson calls 'wood henges' - like Stonehenge, but made of wooden posts - which he believes may be one of a kind in the U.S.
     But there may be an even more remarkable discovery: Linderman says scientists are starting tests on what looks like evidence of lead smelting, a practice that, until now, was only seen in North America after the arrival of the French, 1,000 years after the Hopewell Tradition. Lead smelting is just one of the many questions archaeologists will be targeting in upcoming digs that they hope will clear up at least a few of the Mann Hopewell Site's - and American prehistory's - mysteries. "It's a sleeping giant," says museum curator Greenan, "and it's going to take its place as one of the most important archaeological sites in North America."

Edited from NPR (3 January 2011)