by the designs of the Italian Renaissance architect Andrea Palladio (1508–1580). Palladio's work was strongly based on the symmetry, perspective, and values of the formal classical temple architecture of the Ancient Greeks and Romans. From the 17th century, Palladio's interpretation of this classical architecture was adapted as the style known as Palladianism. It continued to develop until the end of the 18th century, and continued to be popular in Europe throughout the 19th and early 20th centuries, where it was frequently employed in the design of public and municipal buildings. Baroque architecture began in 16th-century Italy. It took the Roman vocabulary of Renaissance architecture and used it in a new rhetorical and theatrical fashion. It was, initially at least, directly linked to the Counter-Reformation, a movement within the Catholic Church to reform itself in response to the Protestant Reformation. Baroque was characterized by new explorations of form, light, and shadow, and a freer treatment of classical elements. It reached its extreme form in the Rococo style. 19th-century architecture Revivalism was a hallmark of nineteenth-century European architecture. Revivals of the Romanesque, Gothic, Renaissance, and Baroque styles all took place, alongside revivals of the Classical styles. Regional styles, such as English Tudor, were also revived, as well as non-European styles, such as Chinese (Chinoiserie) and Egyptian. These revivals often used elements of the original style in a freer way than original examples, sometimes borrowing from multiple styles at once. At Alnwick Castle, for example, Gothic revival elements were added to the exterior of the original medieval castle, while the interiors were designed in a Renaissance style. Art Nouveau architecture was a reaction against the eclectic styles which dominated European architecture in the second half of the 19th century. It was expressed through decoration. The buildings were covered with ornament in curving forms, based on flowers, plants, or animals: butterflies, peacocks, swans, irises, cyclamens, orchids, and water lilies. Façades were asymmetrical, and often decorated with polychrome ceramic tiles. The decoration usually suggested movement; there was no distinction between the structure and the ornament. 20th-century and modern architecture Art Deco architecture began in Brussels in 1903–4. Early buildings had clean lines, rectangular forms, and no decoration on the facades; they marked a clean break with the art nouveau style. After the First World War, art deco buildings of steel and reinforced concrete began to appear in large cities across Europe and the United States.