There are a couple of streets in our part of Seattle, down near the waterfront where the avenues have names instead of numbers. You’d say that they run parallel to each other — but then you’d be mighty surprised when they intersect.
Not once, but twice.
Each of them is still one-way for part of its length — they formed what the traffic guys call a “couplet.” When the Alaskan Way Viaduct still stood, Elliott provided the southbound onramp, and Western was the last northbound exit before the Battery Street Tunnel. Each still shows the marks of an industrial past, but also sports modern apartment buildings, tech company headquarters, and some big civic improvements.
Where to start? Western Avenue begins at Yesler Way, the street from which downtown addresses are numbered. South of here, a street or avenue would have “South” in its name. 
From this intersection, in the picture above, Western takes off to the left, passing offices, warehouses, design firms and residences — including the Harbor Steps, where we lived in the summer of 2009, during our first year as semi-nomads.
After a dozen blocks or so, Western runs by the back of the Pike Place Market.
There’s a little jog just as Western meets the Market’s northwest corner, and a pretty little commons, Victor Steinbrueck Park.
A block north, at Lenora Street, is the place where Western meets (or parts with) Elliott Way:
We’re clearly in Belltown now. That’s Elliott coming in on the left; Western Avenue, on the right, continues north-westerly, and in another ten blocks or so it meets Denny Way. What happens there is a little surprising.
Like Yesler to the south, Denny defines the edge of another street grid. North of there, addresses reset to zero and avenues get a “directional” name. But Denny can only go so far; in the picture below, taken from near Western, Denny is hardly more than a couple of parking lots straddling Elliott Avenue, serving however to transform it into Elliot Ave W.
This vestigial portion of Denny Way isn’t apparent to the casual visitor. If you drive west from, say, the Space Needle, and you stay in the left lane as the roadway curves around, you’ll find yourself initially on Denny, then on Western for a couple of blocks, then on Elliott, and then, about a mile later, on 15th Ave W, headed for the Ballard Bridge.
Looking back, it’s easy to see what happened. In the picture below, Western Ave W is on the left. The red truck at the top of the hill is waiting to cross what would be W Denny Way. Elliott Ave W, on the right, looks like it might be just an offramp, but it is a two-way street for the five blocks between here and Broad.
In the picture below, the low building in the middle distance is the headquarters of Seattle Art Museum’s Olympic Sculpture Park. Elliott Avenue runs through the park from left to right — under part of it in fact — surfacing near that green sign at the intersection with Broad Street. Just beyond are the Olympus Apartments, where we stayed one summer.
Alaskan Way was the other parallel thoroughfare here. Built on pilings out over the water, it was originally called Railroad Avenue, for the tracks that served the docks. Cars eventually edged out most of the trains, but the fact remains: in the picture above, if you want to take Broad Street that one more block down to Alaskan Way, you still have to cross the tracks.
Further south, the tracks disappear into a tunnel under downtown; but if you’re a visitor, Alaskan Way is itself an obstacle to tourism, since Ivar’s, Ye Olde Curiosity Shop, the ferries and the tour boats are all on the other side.
With the Viaduct gone, the City had some traffic engineering to do, and a lot more land to do it with. Some of the solutions are quite grand — there’s a feature that’s equal parts bridge and aquarium, for instance. But Alaskan Way is not what it once was. There’s a new street, amazingly called Elliott Way, that doubles Alaskan for a stretch and then, after running north and uphill a bit, actually itself seems again to split into Western Avenue and Elliott Avenue (after crossing Elliott Avenue once), just a block north of the place where Western does the same thing. Here’s the intersection of Elliott and Elliott:
A close look at the street signs in the middle of the photograph shows that Elliott Way also bears the honorary name Dzidzilalich, local for “little crossing-over place.” This had been proposed as the official name, but the City may have lacked the courage for that or to name it for somebody new; so the Elliott name has simply been repeated again. There’s an explanation of these matters at the website of local historian Benjamin Lukoff, the excellent Writes of Way.
Seattle streets offer a lot of oddities, but this area seems almost deliberately confusing. And we haven’t even mentioned Post Alley.