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That "Lucy" fossil was not notable because of some random footprints ... this was just made up by whoever posted that video lmao. Also, what museums do with fossils doesn't influence the work of evolution biologists. They don't walk into a museum, look at fake fossils and come up with random theories. Science doesn't work like that. Biologists concluded from the anatomy of the bones that were found (which was about 40% of a complete skeleton) that it must have been an upright walking ape, something that was previously thought to have occurred much later I believe. Tons of fossils representing various stages of human evolution were found before AND after "Lucy". Lucy is, and never was the only "link" between apes and humans. This is again false information spread by creationists. Just do some simple research and you will find out that this is true. 

Can you please link me to some other ape-human links ?

A nice list of transitional fossils can be found here: https://en.wikipedia.org/wiki/List_of_transitional_fossils#Human_evolution

Also something that should be noted: 

Biologists / Paleontologists / whatever they're called don't just make their conclusions from pictures of fossils (like all these YT videos). It's much more complex than that. The most important part is analysing DNA (which can be found even in single bone parts) and comparing genoms.. of course things like skeleton structure, soft tissue (which is rarely preserved), etc. are also important but DNA is the most important.