I remember watching a video about marsupials when I was a kid, and one of the most memorable pieces of it was about an extinct animal called the thylacine.
The portion about the thylacine included black-and-white footage of the last thylacine. Something about those images and the story of the animal's extinction struck me. Now, I wonder if the effect was like seeing a ghost (the lingering image of something no longer here in physical form).
Well, two days ago, I read an article in The New York Times about a researcher who had gone to Australia to see rock art of the thylacine. The article has some great stuff about our relationship with nature, and it triggered the memory of that video I watched as a kid (it even has a video with some of that footage of the last thylacine). The effect was much the same as it was when I was younger.