A Styrofoam mountain and tunnel for model trains
We saw this in a store in Bristol Pa. It was identical to one I had as a kid.
When I was a kid, model train layouts were very popular. My Dad would build a 4′ x 8′ set every year. It had “O” gauge on the outside and HO on the inside track. He would get moss and small twigs/branches/ferns while out small game hunting to use for the platform. One thing I remembered was a styrofoam mountain tunnel. That particular tunnel must have been more popular than I realized. Almost 50 years later, I saw one in a hobby store. That brought back a lot of good memories.