Three years after a flood wiped out part of a bridge spanning the Elkhorn River in Neligh, residents of the small northeastern Nebraska city received a festive surprise: an anonymous $650,000 donation to rebuild the historic structure.

The city received a check last week from the donor's Chicago-based attorney, saying they could use it to rebuild the steel-truss Old Mill Bridge on the condition that residents never try to discover who contributed the money. If city officials learn the donor's identity by accident, they are sworn to secrecy.

"I was amazed when I first heard - and then we had to keep it quiet for a month or two," said Neligh Mayor Jeri Anderson.

The bridge on the city's southern edge had just turned 100 years old in 2010 when a flood swept a section of the structure away and devoured about 100 feet of the Elkhorn River's south bank. - AP