The Large and the Small
Two videos watched several years apart, which struck me in a similar way.
The first, "Journey to the Andromeda Galaxy," made me realize how big the universe is. Like any good engineer, I knew it was big... but not that big. Watch it, it's a fascinating mini-documentary that turns our sense of scale in space and time upside down.
For the infinitely small, a very short video: a protein "walking" along a microtubule. As I speak, billions of proteins are strolling along inside your cells.
As Pascal said: here we are, lost between these two infinities. Good night.