BUCKSPORT (AP) – The Maine Department of Transportation on Tuesday unveiled the final plan for a new Waldo-Hancock Bridge spanning the Penobscot River that includes a 420-foot observation tower.

The $56 million contract calls for Cianbro Corp. and Reed & Reed LLC to complete construction by late 2006, said MDOT Commissioner David Cole.

The tower, offering commanding views of Fort Knox, the Penobscot River and surrounding towns, will make the cable-stayed bridge distinctive, much like the 72-year-old suspension bridge it replaces.

“There will be nothing like this anywhere else in the country and we expect it will give people another great reason to visit this part of Maine’s coast,” Cole said Tuesday in a statement.

Visitors will reach the 12-foot by 24-foot glass-enclosed observatory by entering the 150-year-old fort, and then either driving or walking down a new road to the base of the pylon. An elevator will carry six to eight people at a time to the two-level observatory.

The old bridge was being restored in the summer of 2003 when problems on the two suspension cables came to light. Engineers later determined that building a new bridge was the only long-term solution.

Total cost of the new bridge is estimated at $84 million. Early estimates from bidders were close to $105 million for the entire project.

The target price for the total bridge cost was $75 million. But Cole said it was not possible to complete the project for that sum at a time when escalating petroleum prices have driven up the cost of many construction materials.

Concrete has grown 8 percent in price and steel rebar is up 30 percent in the past year. Asphalt, plastics and all delivery costs have also grown.