The 10 euro note depicts a romanesque arch. The romanesque period represents the style in Europe from the 6th to 10th century. The style is called romanesque because of its similarity to the classical style.
The 20 represents the next phase in european architecture. The 20 depicts a gothic style, which was common from the 12th century to the 16th century. The gothic is characterized by its pointed arches and flying buttresses.
The 200 euro note furthers our progression trail. The 200 depicts Art Nouveau architecture, a style common during the 19th and 20th centuries. Art Nouveau buildings usually used nature elements and curving shapes.
The 100 euro note depicts the next evolution of european architecture. The Baroque period was from the 17th century to mid 18th century. Extravagance was most closely associated with the Baroque period.