Minnesota Department of Transportation crews will move the main span of the new Hastings bridge into place this weekend.
The current bridge will be closed at least through Monday. Workers assembled the new span just west of its final destination.
MnDOT says the existing Highway 61 Bridge spanning the Mississippi River is "functionally obsolete." As part of the $120 million project, crews assembled a new bridge near Lock and Dam #2, upstream from Hastings.
Kirsten Klein, a MnDOT spokeswoman, says workers have lowered the huge part onto barges and are floating it downstream, adding that they will use a rail system to lift the bridge into place over three days.
"It is historic," she said. "I think maybe floating down the river might be the most impressive thing; otherwise, everything else is going to kind of move slow."
MnDOT is streaming the action live on its website, "so people can stay at home and not have to worry about crowds if they do that," Klein said.
Klein says assembling the bridge elsewhere and floating it into place reduces the time that roads are closed to traffic. The Hastings bridge will be the longest free-standing tied-arch bridge in North America.