What If The Earth Were Hollow?

What if the Earth were hollow? You can get fast facts from minutephysics in less than four minutes. There are some surprising facts.  Coriolis effect explained.  The Kola Superdeep Borehole in Russia addressed as another topic. This video doesn't cover "Hollow Earth" theory, but rather does hypothetical measurements of falling objects through a hole if one were drilled through the Earth.  How fast Earth rotates - in what direction - find out!