I recently made this short video for a teacher wanting to demonstrate how gravitational lensing works by simulating a Saturn-sized black hole passing through the inner harbor of Baltimore. Follow me on Twitter: @DeepAstronomy Follow DeepAstronomy on Google+ http://google.com/+DeepAstronomy http://google.com/+TonyDarnell We also have a great Google+ Community, come share your thoughts and join the discussion! https://plus.google.com/communities/109849939648748938781