Michele wanted to find a high vantage point from which to snap a few pix of downtown Grand Rapids, Michigan. She's a native of these parts, and had some blushing memories as we drove up to, and then walked along the lip of a very high bank. Turns out it is a city park that she visited as a teenager. Hmm.

I noticed this guardrail, and what looked like a spillway behind it. I went over and had a look.

This is the top of what I thought looked like a spillway. It is actually a very old, very decayed concrete stairway. You can see, in the foreground, the iron reinforcing rods where steps once were. Note also the substantial tree growing between the side rails. Finally, if you look down, down, down the steps, you'll see a dark semi-circle. That circle is really a shadow and a bower of vegetation overhanging the steps. It is/was big enough to walk through. Climbing up these steps long ago must have been quite a trek.
One theory offered after I mentioned the stairway to an acquaintance was that it once provided access from the residences on the hill to the extensive factories by the river below. Makes sense.
And then there were the young folks of the day, and maybe a few generations beyond. A weekend. A lovely overlook of the city. The westerly setting sun. 'Johnnie, I'm getting a little cold.' So much history.
That would have been considerably before Michele's teenage days, but the motivation to climb those long, rewarding stairs, might have been similar.
(If I am murdered by the time you read this, you will know who to suspect.)
By 
You're not going to be murdered...And no cold shoulder, either!
I love these kinds of mysterious finds. Your speculation as to history of these stairs is very plausible and interesting. The picture looking down the stairs is a great shot of the viewpoint from up there. What a hike, indeed! I can't imagine having the energy for that climb after working in a factory all day.
I am disappointed that Michele didn't regale us with tales of her experiences there. But that would have probably changed my beautiful impression of her *wink*.