MORTON, MINN.-- Lt. Col. Carl Colwell was all set to retire from the Pentagon when the hijacked plane struck.

"The world turns, and things change," he says.

After graduating from Morton High School 35 years ago, Colwell headed to West Point and then spent 21 years on active duty. He'd spent his last three as an Army strategic planner before selling his house and preparing to move his family to Louisiana.

Colwell had just met with his daughter Karin's teachers and was riding the 8 a.m. train past Arlington National Cemetery when the brakes on the Blue Line screeched to a stop. He walked a mile south along the rails on Sept. 11, 2001.

"I looked down and saw the black smoke rising from the Pentagon," he says. "I'd been on the train for 45 minutes when the plane hit, and didn't have any clue."

The Army asked him to stick around, and he did for nearly four years. But then something pulled him home to the ancient rocks along the Minnesota River Valley a few hours west of the Twin Cities. Colwell's great-grandparents had emigrated from Ireland and Norway in the 1880s and farmed this land. His mother was ailing, and his younger daughter, Mikala, was beginning school.

It was time to come home.

Colwell is now in his sixth and final year as mayor of Morton, pop. 450. He's also the director of the Renville County Historical Society. A couple of years ago, he purchased the old brick schoolhouse he attended, which was sitting vacant, along with 14 acres he's converted into a natural science and research area.

Starting next fall, Colwell hopes to bring student groups to the new Minnesota Valley History Learning Center to learn about the area's rich past (see video at www.startribune.com/a1099).

Outdoor geology lessons will feature what's known as Morton Gneiss, some of the planet's oldest rock at 3.6 billion years, through which glacial rivers carved out this valley after the last Ice Age.

Some 12,000 years later, the area was the epicenter of the 1862 U.S.-Dakota War, where broken treaties and late government payments pushed starving Indians toward a six-week war that killed more than 500 immigrant settlers and soldiers and led to their expulsion from the Dakota homeland.

"There is an unbelievable amount of significant history here," Colwell says. "Events happened here at a critical, formative period for the United States. This violent conflict really hasn't been resolved to anyone's satisfaction."

He hopes the new learning center will help Morton, and the state, appreciate this area.

"This is a touchstone and I hope people will develop a sense of place as much as I have," Colwell says.

He and his wife, Angie, live in an 118-year-old house that his parents originally bought 50 years ago. Its basement foundation walls are made of the old Morton Gneiss rock he cherishes so deeply.

CURT BROWN