At some point during the Industrial Revolution, noise outside their cave awakens the Autobot Bumblebee. He ventures outside the cave to discover the planet's new dominant species — man, and that they have developed steam powered technology and the capacity to build railroads.
During the Industrial Revolution, noise from outside a cave roused the Autobot Bumblebee. He ventured out to find the planet's new ruling species: humans, who had advanced their technology with steam engines and built railways.