Submitted by SounderBruce, who says:

Of Seattle’s many, many unsuccessful attempts to build a rapid transit system, none sting more than the century-old Bogue Plan. Rejected by a landslide of 10,000 votes (out of 40,000 total cast) on March 5, 1912, Virgil Bogue’s ambitious comprehensive plan to convert the regraded remains of Denny Hill into a Beaux-Arts civic center reminiscent of European city centers would have been well served by 91 miles of rapid transit lines from as far away as Tukwila, Edmonds and Bothell. Bogue was not satisfied with the existing streetcar system, commenting that its frequent stops would not adequately serve future surburban riders; the streetcar network would be scrapped in favor of electric trolleybuses thirty years later.

Among the long list of specific routes was a subway under Third Avenue whose stations would have had entrances inside of mercantile establishments (familiar to users of Westlake Station). Other proposed corridors, such as the Ballard-U District and West Seattle lines, are now under consideration for the next expansion of Sound Transit’s Link Light Rail system, expected to be put to public vote in 2016.

Transit Maps says:

What a beautiful map! And what ambitious plans! It is to be noted here how many of the rapid transit lines were to be underground or elevated, with such lines spreading far out into the suburbs. Many of the general transit corridors seem very familiar even now, although a lot of that has to do with Seattle’s constricting geography. I’m intrigued by the split in line 5 around Green Lake (northbound to the east, southbound to the west?), while the routing of line 4 through Queen Anne just seems like the work of a madman.

Source: SounderBruce/Flickr