The Secret Genius of Modern Life Series 2: Episode Guide & Ratings

Hannah gains access to a top-secret site where anonymous staff and the latest tech work to make the British passport one of the most secure documents on the planet. She reveals the World War I spy craft hidden in the pages of every passport and takes a look into how modern ID checks were shaped by the hunt for a 19th-century French serial killer and 1970s psychedelic art.

Hannah takes a look at the vacuum cleaner, going behind the scenes with Dyson and discovering how the motor in their latest vacuum spins nine times faster than that of a Formula One race car. She finds out why a wheezy janitor in the 1900s took inspiration from a sewing machine to create the first popular, portable vacuum. And she comes face to face with a colony of creepy crawlies whose job is to help us fight the filth.

With over six billion of them across the planet, smartphones have changed the modern world. With rare access to electronics giant Samsung, Hannah uncovers the technological game-changers that have made the smartphone a reality. She finds out how 1940s comic book hero Dick Tracy inspired the first mobile phone, discovers why the invention of the digital camera led to one of the biggest commercial blunders of all time, and reveals what a 2010 South Korean sausage frenzy can tell us about touchscreens.

Hannah Fry discovers the hidden WW2 radar technology that heats up baked beans, learns the legend of the melted candy bar in an engineer’s pocket that kick-started a kitchen revolution, and puts her life on the line to demonstrate why microwaves zap food but not people!

Headphones: these marvels of miniaturisation are worn by 30 million people in the UK. Hannah Fry visits Bose to find out how the teeny earbud tech works and meets the human testers with ‘golden ears’.

Hannah goes behind the scenes to look at the technology behind the lift, entering a 246m high lift shaft to test everything from the brakes to her own fear of heights. Along the way, she finds out how rickety 19th-century coal mines made lifts safer, gets to grips with a piece of medieval siege technology still used in lifts today, and discovers how an 1850s PR stunt changed the modern skyline forever.