Texas is home to the earliest American settlers, according to a landmark archeological investigation featured in a new documentary. The Stones Are Speaking, now available on Apple TV, Amazon, and Google Play, shares the journey of archaeologist Michael Collins, who discovered evidence of ancient settlers on a site in Central Texas.

Collins started his initial investigation on the Gault Site, located about an hour north of Austin in Florence, in 1991. This isn't the first time Texans have heard about the site's findings — the project was recognized by the Archeological Institute of America as one of the top 10 discoveries of 2018 — but the documentary gives a look at exactly what happened, including footage from the dig.

Written, produced, and directed by Olive Talley, the documentary follows Collins and his team as they unearth more than 2 million ancient artifacts on 30 acres of land that was previously looted and used as a pay-to-dig site. The archeological dig turned up tools from a Paleoindian culture that lived in North America roughly 13,500 years ago, called the Clovis culture, and a mammoth jawbone.

”It was the biggest nest of Clovis artifacts I’ve ever seen,” Collins said in the documentary trailer. “It’s been abused and looted, but still has an enormous story to tell.”

The team also uncovered artifacts that revealed a human presence in the area — older than the Clovis culture — up to 20,000 years ago, near the end of the last ice age. This shocking discovery is essentially rewriting the history of the oldest known human origins in the Americas, which was previously considered 13,000 years old.

Collins, who has spent his life searching for evidence of earlier life in the Americas, saved the Gault Site when he purchased it in 2007 and donated it to the Archaeological Conservancy. It has since created a new theory as to when humans migrated from Asia to the Americas.

The documentary first premiered at the Austin Film Festival last October, where it won the audience award for best Texas Independent Feature, and was previously part of the Made in Texas Film Series on Texas PBS Stations in March.

“I hope the film inspires people,” Talley said in a press release. “In this case, to preserve history before it’s irretrievably lost. If we could all be like Mike Collins, the world would be a better place. He gave selflessly to others, and shared his knowledge, educated students, and ultimately saved precious history for the benefit of all of us.”