Andrew Graham-Dixon continues his exploration of German art by looking at the tumultuous 19th century and early 20th century, and how artists were at the forefront of Germany's drive to become a single nation. Andrew travels to the north and the coastal town of Griefswald, the birthplace of Caspar David Friedrich, the most influential of the German Romantics, to discover how the Baltic coast impacted on his mysterious paintings of the German landscape. He also visits Berlin and explores the art of the powerful Prussian state, which would spearhead the unification of Germany in 1871. The episode ends with the outbreak of the World War I and the attempts of artists Franz Marc and Otto Dix to rationalise the catastrophic experiences of the world's first technological war, a war driven by the innovations of Prussia.

• Andrew Graham-Dixon