Dr. Gary Greenberg
This animation shows how the world's largest tunneling machine works.
Andreas Raptopoulos
Planet Earth is this solid thing you are standing on right now. In your everyday life you don't really waste a thought about how amazing this is. A giant, ancient, hot rock. How did it come into existence and how big is it really? You will be surprised. The ground you are standing on is just a very, very small part of the big picture.