Paved with gold.

David Bellamy researches the history of medicinal plants and finds that many of them are still used as vital ingredients of modern medicines. Part 1: "Paved with Gold" David Bellamy tours London's streets and finds medicinal plants still growing there. He compares an early 20th century pharmacy with its modern counterpart and visits the National Institute of Medical Herbalists whose 4-year course includes basic medical training.