The underside of the Alaskan Way Viaduct has always been its own ecosystem, totally distinct from the tourist-friendly waterfront to the west and the towers of glass to the east. It's always been a land of 24-hour darkness where Seattle's most unwanted and unseen citizens gather to rest, do business, and hide from the perpetual harassment they suffer on the streets. But construction on the waterfront tunnel and the seawall have transformed the pedestrian experience under the viaduct into a completely different kind of atmosphere.

Walking underneath the length of the viaduct from south to north, the first thing I notice—how could you not?—is a gigantic wall that stretches for blocks. This temporary wall, erected by construction crews, completely blocks the view of the water and somehow lends the under-viaduct an even more hopeless, isolating air. Rather than a covered outdoor space, it feels like you're in a dirty box tipped on its side. For almost the entirety of the two miles of walk-underable viaduct, the roar of construction equipment makes it impossible to carry on a conversation with anyone you're walking with, let alone hear someone on your phone. It makes the area's old creepy vibe even more nightmarish and aggressive.

Heading north, I'm struck by how difficult the viaduct is for pedestrians. At certain spots, the sidewalk simply comes to an end, leaving me in part-street/part-parking-spot no-man's-land. If a car were to hit me, no judge in the land would prosecute the driver. Near Yesler, homeless people have set up tents under the viaduct. It's a settlement, and a fairly well-established one, with some laundry hanging out to dry and a wheelchair packed up next to one of the giant concrete pillars.

A little farther north, by the ferry terminals, the viaduct normalizes into something similar to its old self. Chain-link fences appear, so sunlight reappears. Tourists wander around, clutching their purses warily, in search of a clear path to the Great Wheel through all the mayhem. People on bikes try to negotiate the streets without becoming wrapped around a dump truck's bumper. A FedEx truck chases after two people on Pronto bikes with terrified looks on their faces. Once you get past Pike Place Market, the viaduct reverts back toward the hopelessly seedy. One set of stairs is infested with a gigantic nest of rats screeching louder than the distant bulldozers. They're so brazen, these rats aren't even trying to hide from human eyes anymore.

My God, it's an ugly walk—clearly the ugliest walk in Seattle. Compare the 40-minute stroll beneath the viaduct with a similar distance around the southern tip of Lake Union and it feels not like two different cities, but two different continents. Last week, I was in South Lake Union, crossing Lake Union Park, when I noticed the Lake Union Park bridge, a beautiful pedestrian bridge that I've crossed on multiple occasions, is sealed off with chain-link fence and an apologetic sign explaining that the "bridge is closed while Seattle Parks and Recreation conducts a geotechnical examination to determine possible repairs" due to "the east butment" of the bridge, which "has moved," rendering the bridge "no longer within acceptable structural tolerances."

This was a surprising sign in a city that at the same time still lets 110,000 cars onto the viaduct every day. I asked Joelle Hammerstad from Seattle Parks and Recreation for more information about the Lake Union Park bridge. She said that in October of 2014, Parks and Recreation staff noticed that the butment "moved sideways" and they closed the bridge for an upcoming inspection "to complete a geotechnical assessment of the area to determine the reasons behind the movement and develop corrective measures."

The tiny bridge was constructed by Big R Bridge from Colorado, and it opened in 2008. When I asked whether Parks and Recreation would do anything to protect kayakers who float under the pedestrians on that bridge—I've kayaked under that bridge on multiple occasions—Hammerstad replied, "We will fabricate signs to hang from the bridge to warn kayakers. They will be installed by next week."

So you can understand my sense of disconnect standing underneath the viaduct at First and Battery, weighing the potential harm of a collapsing viaduct against the potential harm of a collapsing pedestrian bridge. It's hard, these days, to stare at the viaduct and not picture it crashing down to the ground. Sometimes, when traffic is roaring and construction cranes are doing their clumsy dance around what appears to be a crumbling pillar, it feels as though simply staring at the viaduct too hard could cause it to collapse. Why doesn't the city demonstrate the same concern for those wobbly tourists and frightened bicyclists and people living in tents that it demonstrates for kayakers on South Lake Union? How is it that a bridge that could kill 20 people is considered by the City of Seattle to be a greater hazard than one that could kill hundreds or thousands? recommended