In the clip from Genius by Stephen Hawking, three volunteers set out to learn just how old the Earth really is. Located in beautiful countryside, the volunteers are presented with a trail of fireworks to visualize how old the Earth is, and therefore life. Each firework set off represents 250,000 years. This means that one flash is 50,000 years longer than the age of our species, the Homo Sapiens. In one second four flashes can go off, this means that four flashes are equal to one million years. Using a stopwatch, the volunteers must follow the firework trail and discover how old the Earth is.