"A cat's eyes are windows enabling us to see into another world." - Irish Legend
One of my former neighborhoods had a large, beautiful, gray tomcat who was very regular in his routine. I liked to watch him make his daily trek. One day, I noticed he was off duty and wondered what might be the cause then forgot about it.
Later, I heard a muffled sound and realized it was a "meow" -- coming from somewhere inside my house. I began to track the sound and quickly figured out it was a call for help.
Somehow, during reconstruction work, "Mister D." (Devious) had fallen down an open heating vent and was trapped in the belly of the newly installed furnace. The time of year was in his favor. He and I were both glad to see each other.
Matted fur and a sour odor gave him away - he had been there for a day or two. Jumping into my arms when I opened the vent, it was the best hug I could have asked for. He was physically unharmed. I updated his owners and set him free outside to let him regain his composure and dignity.
Mister D maintained his route but kept his visits outside the house after that, much to the delight of the young child who moved in with his family. They became fast friends.
This cat likes to keep souvenirs of his neighborhood forays ...