Humans are an ingenious species. Though we've been on the planet for a relatively short amount of time (Earth is 4.5 billion years old), modern Homo sapiens have dreamed up and created some amazing, sometimes far-out, things. From the moment someone bashed a rock on the ground to make the first sharp-edged tool, to the debut of the wheel to the development of Mars rovers and the Internet, several key advancements stand out as particularly revolutionary. Here are our top picks for the most important inventions of all time, along with the science behind the invention and how they came about.