Built in 1936, the 411-foot long, cast-in-place arch bridge Rainbow Bridge on Highway 55 spans the Payette River. A southern Idaho icon, it is on the Historic Register.
As one of the major north-south routes, it carries a tremendous amount of traffic, which makes this old photograph from my grandmother’s album especially great. A person would not be able to catch just one vehicle on the road in this day and age.
More info at Idaho Transportation Department
Thanks to Michael Lai’s post for reminding me of this great, old photograph.