Arguably, one of the most important concepts one learns from studying astronomy, is the astounding vastness of the cosmos. This vastness extends not only out to the very VERY large and far away - it extends down to the very VERY small.
The human mind is ill-equipped to grasp the scale of the universe - but we can sure give it a try! Over the last few decades, several videos have been made showing the scale of the Universe.
1977: The iconic Powers of Ten video - remember: this was made before computer graphics:
1980: Cosmos: "The Edge of Forever" - Carl Sagan discusses the origins and structure of the Universe, and gives us the quote: "We are made of star stuff; we are a way for the Cosmos to know itself." Here is the intro to the episode:
1996: IMAX movie Cosmic Voyage - narrated by Morgan Freeman. An updated version of Powers of Ten, with some nice computer graphics.
1997: The opening scene from the movie Contact - A personal favorite of mine:
2012: The Scale of the Universe 2 Video:
2012: The Scale of the Universe 2 Interactive: http://htwins.net/scale2/ (Warning! This thing is WAY too much fun, and you can lose a lot more time playing with this than you might realize...)
2015: Business Insider's Scale of the Universe - VERY NICELY DONE! Uses imagery from "The Scale of the Universe 2"
Other videos/sites of interest:
2011: Millennium Simulation Project: Modeling the universe at very large scales.
Millennium Simulation Project Homepage: http://wwwmpa.mpa-garching.mpg.de/galform/virgo/millennium/
2014: Google's 100,000 Stars: http://stars.chromeexperiments.com/ - An interactive 3D visualization of the stellar neighborhood, including over 100,000 nearby stars.
2014: Riding Light - animation illustrating the real-time journey of a photon of light emitted from the surface of the sun and traveling across a portion of the solar system.
2014: Across the Universe: Hubble Ultra Deep Field 3D Visualization
Planet and Star Size Comparison: