THIS MIGHT BE one of my favorite examples of Seattle trivia. Do you know why the clearance of the Washington Park Arboretum aqueduct is so low? If you guessed it’s due to the smaller size of vehicles back in 1911, when the footbridge opened over the lovely boulevard below, you’d be partially right. But it’s also because it had to be placed at a certain elevation over the road to fulfill its original purpose: disguising a sewer pipeline.

The picturesque footbridge, which is a city landmark and also on the National Register of Historic Places, is often referred to by different names. Arboretum Aqueduct has a nice ring to it. Arboretum Sewer Trestle is less euphemistic but, ew. The one I like the most has to be Wilcox Footbridge, which honors the legacy of the architect who so cleverly turned a utilitarian pipeline cover into an artful passageway.

If an urban hike leads you to the Arboretum soon, you might see this view I sketched if you walk to the south side of the trestle. From this angle, the elegant concrete-and-brick design spanning all six arches of the footbridge is easier to appreciate. Just watch out for any taller-than-9-foot vehicles that might need to use that patch of dirt to turn around.