Door Within a Door

Here's a fun little side story from my tapestry trip to Milwaukee.  

We stayed at the Knickerbocker Hotel.  It was built in the late 1920's as a residential hotel.  They had a mini-town square on the first floor, including shops, a beauty salon, and a grocery store.  (I always read all the little booklets in hotel rooms.)

Have any of you ever seen a door like this one?  Here it is closed.

Here is the door-within-a-door, open.

Here's the informative sticker, explaining how the door works.

And here's the hallway view.  You can see the two locks.  

This surely is a nostalgic peek into a past era!  If you look back at the open door photo above, you can see, on the left, a little sleeve holder so nothing gets caught or stuck during the closings and openings.  So thoughtful and secure!