150 years of Levi’s 501 blue jeans

In 1873 Levi Strauss and his tailor, Jacob Davis, created the modern denim pants known as blue jeans, designed for workmen. Today they are a clothing staple, and an icon of fashion. Correspondent Serena Altschul explores the history of blue jeans, and visits the Levi’s laboratory where new denim finishes are being tested.