Home Insurance Building, widely considered to be the first true skyscraper due to its use of a structural steel frame. Built in 1884.
Pioneer Building, was the tallest building west of Chicago, surpassing St. Paul's previous tallest, the Globe Building when it was completed in 1889. Also early home of Minnesota's first newspaper, now known as the Pioneer Press, and home of the world's first telephone answering service, implemented in 1927 [1]
Hamilton Building, first building in Portland designed in the Classical Revival style, completed in 1893