Secrets of the Brain

Theoretical physicist Professor Jim Al-Khalili goes on a journey through 600 million years of evolution to uncover how the human brain, the most complex structure known in the universe, came to exist.With some 100 billion neurons and over 100 trillion connections - more than all the stars in the Milky Way - the human brain is one of nature's greatest achievements. But how did something so incredibly sophisticated evolve from its simple beginnings?

Jim watches primates in action to see how they tackle survival challenges, revealing the clever tricks that shaped our thinking. But the real breakthrough came when brains learned to be social. Teaming up with his wife, Jim investigates how relationships and friendships made people more intelligent.With AI getting smarter by the day, Jim wants to know what makes biological brains so special. Through scans, fossil discoveries and cutting-edge research, he uncovers what makes the brain so hard to emulate.