The Secret Genius of Modern Life - Season 3

Hannah takes a look at the air fryer – a device that is rapidly taking over people's kitchens, cooking up everything from bread rolls to baked Alaska and almost making ovens obsolete.

Hannah hits the production line with appliance giants Bosch to find the lifeblood at the heart of every fridge and gets a lesson in carrot droop.

The rollercoaster has been sending our hearts racing and stomachs dropping for over a century, and today millions of us get our kicks on these topsy-turvy, dare-devil joyriders. Hannah gets the inside story on the UK's newest, tallest and fastest rollercoaster – Thorpe Park's Hyperia. She uncovers the wild origins of the modern day coaster and finds out how some dodgy French physics in the 19th century, NASA rocket scientists and an ambitious cartoonist called Walt delivered the ultimate thrill machine.

The rise of the smart doorbell is one of the great tech success stories of the 21st century, and these security gadgets are now taking over people's doorsteps.

Hannah heads to Los Angeles to talk to market leaders Ring and take a deep dive into doorbell history, discovering how a garage tinkerer who played with sharks, some Soviet spy tech and a student desperate for a drink all led to this technological phenomenon.

Britain's 2,300 miles of motorway are the backbone of the country, and without them, it'd probably all grind to a halt.

Hannah takes a drive to the National Highways control centre for the UK's busiest motorway to meet the team that keep these super-roads running 24/7. And she discovers how a mathematician with a passion for wild swimming, a Formula 1 legend and a 1960s road-sign revolution created the modern motorway.