Torre del Oro was built as a watchtower and defensive barrier on the river. The river was used as a mode of defense. A chain was strung through the water from the base of the tower to prevent boats from traveling into the river port. The City Hall was built in the 16th century in high Plateresque style by master architect Diego de Riaño. The façade to Plaza Nueva was built in the 19th century in Neoclassical style. The Palacio de San Telmo, formerly the University of Sailors, and later the Seminary, is now the seat for the Andalusian Autonomous Government. It is one of the most emblematic buildings of baroque architecture, mainly to its world-renowned churrigueresque principal façade and the impressive chapel. The Royal Tobacco Factory is housed on the original site of the first tobacco factory in Europe, a vast 18th-century building in Baroque style and the purported inspiration for the opera Carmen. The Metropol Parasol, in La Encarnación square, is the world's largest wooden structure. A monumental umbrella-like building designed by the German architect Jürgen Mayer, finished in 2011. This modern architecture structure houses the central market and an underground archaeological complex. The terrace roof is a city viewpoint. The General Archive of the Indies, is the repository of extremely valuable archival documents illustrating the history of the Spanish Empire in the Americas and the Philippines. The building itself, an unusually serene and Italianate example of Spanish Renaissance architecture, was designed by Juan de Herrera. The Plaza de España in the Parque de María Luisa (María Luisa Park) was built by the architect Aníbal González for the 1929 Exposición Ibero-Americana. It is an outstanding example of Regionalist Revival Architecture, a bizarre and loftily conceived mixture of diverse historic styles, such as Art Deco and lavishly ornamented with typical glazed tiles. The Moorish urban influences continued and are present in contemporary Seville, for instance in the custom of decorating with plants and small fountains in the courtyards of the houses. However, most buildings of the Moorish aesthetic actually belong to the Mudéjar style of Islamic art, developed under Christian rule and inspired by the Arabic style. Original Moorish buildings are the Patio del Yeso in the Alcázar, the city walls, and the main section of the Giralda, the bell tower of the Seville Cathedral. The neighbourhood of Triana, situated on the west bank of the River Guadalquivir, had