Golden Valley-based Mortenson builds 40-story flagpole, tallest in U.S.

And you thought the new Vikings stadium is a feat of engineering and construction might.

Golden Valley-based Mortenson Construction, which is building the new stadium, recently constructed North America's tallest flagpole.

Located at the Sheboygan, Wis., headquarters of Acuity Insurance, the pole spans 400 feet. That's roughly 40 stories.

Acuity hired Mortenson to build the pole, which is a "symbol of freedom and hope," said the firm's president and CEO, Ben Salzmann. The pole was dedicated last month.

The pole consists of six steel tubes, and Mortenson officials say they used their expertise from the firm's renewable energy group for the project — flagpoles are similar to wind turbine towers.

The flag is four stories tall, and two versions will be used: A 220-pound flag for normal conditions and a 350- pound flag for harsher weather.

The flagpole itself weighs about 420,000 pounds and is designed to withstand temperatures down to 42 degrees below zero.