The Secret Genius Of Modern Life Season 2 is yet to be announced by BBC Two

Did you know that a family feud created two of the world's biggest trainer brands? Hannah Fry visits Ebay's authentication centre, where they are waging war against fake high-value trainers. She discovers how American breakfast waffles transformed our trainer soles, and how an 18th century tea set led to the use of celebrity endorsement.

With around a third of the population now owning fitness trackers, Britain has become a nation obsessed with tracking its every move.

Hannah Fry finds out how 1970s car crashes helped us to count our steps, why high-altitude WWII dog-fights led to a crucial health monitor and how fitness trackers are even being used to catch killers.

Hannah Fry discovers why innovations in meat packing almost derailed the electric car revolution and how a breakthrough in camcorder batteries led to Elon Musk's electric empire, as well as demonstrating how not to drive a multimillion dollar prototype car of the future.

Hannah Fry delves into the inner workings of virtual assistants, such as Google Assistant and Siri, which are now found in almost half of all UK homes.

Hannah goes behind the scenes with Alexa's chief scientist, reveals how secret technology invented to hunt U-boats led to their targeted hearing, and discovers modern wireless networks' debt to a 1940s Hollywood star.

Hannah Fry tucks into the tech behind food delivery apps like Deliveroo and Just Eat, which are now used by 24 million people in the UK.

Hannah meets the R&D team behind food delivery titan Deliveroo, finds out how pensioners ordering Greggs revolutionised food delivery, and discovers how pizza made us fall in love with the internet in the 1990s.

Hannah Fry takes a look at the bank card. This humble piece of plastic is often taken for granted, but it's the digital key to accessing cash and is packed full of extraordinary technological innovations - including some with surprising and sinister origins.

Hannah is granted the first ever TV access to Visa's European bank card data centre, discovers why we have Russian spies to thank for contactless payments, and finds out how the CIA and a 1950s housewife helped kickstart the bank card revolution.