They compartmentalize our homes and - to some degree - our lives.
But one wall in one Ballard home has provided us with a little window into our own past.
And what a fascinating window it is!
"You really do get a sense of the history just walking through the house," homeowner Matt Peters said.
It has stood here for 113 years. Lives and families and hopes and dreams have come and gone.
If these walls could talk.
This year it was time for the walls to change again: during a remodel.
Ramon Santana dug into the kitchen lath and plaster and when the walls came crumbling down, they talked to him.
What did he find?
Newspapers. A lot of newspapers tacked to the walls.
"You know we uncovered (them) and we were like 'wow,' and were wondering what year it was because we always find something but this has got to be the oldest one," Santana said.
There were newspaper dispatches from the past: 1961.
Maybe they were intended as insulation.
Maybe the space between the outside and the inside was just a handy place to dump the days news.
"Seatbelt fixtures will be standard part of 1962 cars," Santana said, reading the headline.
But now, the faded paper trail is like a time capsule.
To browse through them is a revelation.
The city we know now was still in the making.
Another headline reads: "Leif Erickson statue to be erected in Shilshole Bay area."
It's still there, as much a part of Shilshole Bay as the boats themselves.
"Roosevelt High growing, gymnasium taking shape," reads another headline.
Now it's an old gym at an old school, but it's still standing.
And then this one from Feb 21, 1961: "Sale of Space Needle sight approved."
It was just an idea then. Now it's the iconic landmark of an entire region.
But the walls held other surprises.
Under a floor board, more papers and these were twice as old: from 1901.
"We knew the house was built in the early 1900's we didn't know it was quite that old," Peters, the owner said.
Santana reads another headline: "'President (Theodore) Roosevelt appoints Thursday, Nov. 28 as a day of Thanksgiving throughout the nation.,''Wow."
"It's just really interesting to see the things they're talking about. The prices, wow!" Peters said.
Lots on Rainier Avenue were selling for $175.
An 8-room house on two lots cost $1200.
Also, up in the ceiling, another gift from 1901.
"It's like, a homemade skateboard," Santana said.
Crude, archaic and about 75-years ahead of it's time.
And in the then-Ballard News, a wedding announcement reads: Kay Marie Thomas and Thomas Ferguson, nuptials solemnized.
They were married on Feb. 23, 1961.
And they are still together, 52 years later, as we found out.
"Same picture, there it is that's amazing," Thomas Ferguson said.
Still alive--still together--still very much in love.
"I got the greatest girl in the world. I'm the luckiest guy in the world to have this girl," Thomas said.
"She is a girl! She's my girl," he said.
Some things, happily, never change.
Santana left one of the papers tacked up inside that wall.
Then he covered it with real insulation.
And sealed it with dry wall.
Someday, maybe, the walls will talk again.