What’s on telly tonight? Here the TV Times team of expert reviewers highlight the best shows on Friday 21st September

What’s on telly tonight? Here the TV Times team of expert reviewers highlight the best shows on Thursday 20th September

Ancient Invisible Cities, 9pm, BBC2

Dr Michael Scott gallops through the tumultuous history of Istanbul, Turkey’s largest city, in the final instalment of this revealing series. Using the latest 3D scanning technology to expose what history has hidden he goes beyond the surface to a grand and ancient city full of complex engineering centuries ahead of its time. He begins in the huge 1,500-year-old Hagia Sophia, a cathedral built by the Romans, to find out how so much of it has survived for so long. He also explores the ruins of the Great Palace and delves deep beneath the city, through the unassuming doors of a carpet shop, to see an ancient mosaic and holy well. It’s a thrilling end to what’s been a fascinating and unique series. Rating: ****

Britain by Bike, 8pm, Channel 5

George and Larry Lamb finish their two-wheel tour of Britain with a 185-mile trip across the Outer Hebrides. Landing on the world’s only beach runway in Barra before climbing on their bikes, they follow the Hebridean Way, finishing in Lewis. As well as the guys having to contend with wild weather and a menacing bull, Larry’s electric bike plays up. But a cute lamb in a tweed jacket lifts their spirits! Rating: ****

A Discovery of Witches, 9pm, Sky One

After last week’s gripping opening episode, we’re intrigued to see what Diana (Teresa Palmer) does next – we have so many questions! How long can she ignore her overwhelming magical powers? Will she give in to temptation and request the enchanted manuscript from the Bodleian Library one more time? And can she fight the attraction she feels to vampire du jour, Matthew (Matthew Goode)? Well, it’s not just us who want to know the answers – the creatures of Oxford all have their eyes on the mysterious academic, and the dangerous Peter Knox (Owen Teale) is about to take matters into his own hands. Meanwhile, Matthew is conflicted – should he follow his head or his heart? Rating: ****

More previews tomorrow.