<P> Following the Greek War of Independence and the establishment of the Greek Kingdom, Athens was chosen as the capital of the newly independent Greek state in 1834, largely because of historical and sentimental reasons . At the time it was a town of modest size built around the foot of the Acropolis . The first King of Greece, Otto of Bavaria, commissioned the architects Stamatios Kleanthis and Eduard Schaubert to design a modern city plan fit for the capital of a state . </P> <P> The first modern city plan consisted of a triangle defined by the Acropolis, the ancient cemetery of Kerameikos and the new palace of the Bavarian king (now housing the Greek Parliament), so as to highlight the continuity between modern and ancient Athens . Neoclassicism, the international style of this epoch, was the architectural style through which Bavarian, French and Greek architects such as Hansen, Klenze, Boulanger or Kaftantzoglou designed the first important public buildings of the new capital . In 1896, Athens hosted the first modern Olympic Games . During the 1920s a number of Greek refugees, expelled from Asia Minor after the Greco - Turkish War, swelled Athens's population; nevertheless it was most particularly following World War II, and from the 1950s and 1960s, that the population of the city exploded, and Athens experienced a gradual expansion . </P> <P> In the 1980s it became evident that smog from factories and an ever - increasing fleet of automobiles, as well as a lack of adequate free space due to congestion, had evolved into the city's most important challenge . A series of anti-pollution measures taken by the city's authorities in the 1990s, combined with a substantial improvement of the city's infrastructure (including the Attiki Odos motorway, the expansion of the Athens Metro, and the new Athens International Airport), considerably alleviated pollution and transformed Athens into a much more functional city . In 2004 Athens hosted the 2004 Summer Olympics . </P> <P> Athens sprawls across the central plain of Attica that is often referred to as the Athens or Attica Basin (Greek: Λεκανοπέδιο Αττικής). The basin is bounded by four large mountains: Mount Aigaleo to the west, Mount Parnitha to the north, Mount Pentelicus to the northeast and Mount Hymettus to the east . Beyond Mount Aegaleo lies the Thriasian plain, which forms an extension of the central plain to the west . The Saronic Gulf lies to the southwest . Mount Parnitha is the tallest of the four mountains (1,413 m (4,636 ft)), and has been declared a national park . </P>

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