In this first episode Professor Alice Roberts heads to Barts' extraordinary archive, which holds almost 900 years of fascinating and priceless artefacts from the history of the hospital. She's given special access to one of their most precious items dating back to 1137 – a document for a grant signed by Barts's founder, a courtier called Rahere, still bearing its original wax seal.

Across the courtyard in the high-tech King George V Building are ten state-of-the-art catheterisation laboratories, where a crack team of cardiologists use minimally invasive technology to save the lives of thousands of heart patients a year.