There are seven billion humans on Earth, spread across the whole planet. Scientific evidence suggests that most of us can trace our origins to one tiny group of people who left Africa around 70,000 years ago. In this five-part series, Dr Alice Roberts follows the archaeological and genetic footprints of our ancient ancestors to find out how their journeys transformed our species into the humans we are today, and how Homo Sapiens came to dominate the planet.

• Alice Roberts
• Tessa Wojtczak