Extras
Breakthrough: The Ideas That Changed the World
In 1923, Edwin Hubble began the manual process of photographing the Andromeda Nebula.
Discovering the Big Bang
Breakthrough: The Ideas That Changed the World
Learn how clear glass was born - and gave us spectacles almost 800 years ago.
Glass - A New Wonder Material
Breakthrough: The Ideas That Changed the World
How a New York property boom led to the discovery of the distance to the stars.