Plovdiv is the second-largest city in Bulgaria, with a population of 341,567 inhabitants, while 544,628 live in its urban area. It is an important economic, transport, cultural, and educational center. Plovdiv has evidence of habitation since the 6th millennium BC when the first Neolithic settlements were established. It is said to be one of the oldest cities in Europe. Plovdiv was known in the West for most of its recorded history by the name Philippopolis as Philip II of Macedon conquered it in the 4th century BC and gave his name to it. The city was originally a Thracian settlement, later being invaded by Persians, Greeks, Celts, Romans, Goths, Huns, Bulgarians, Slav-Vikings, Crusaders and Turks. On 4 January 1878, Plovdiv was liberated from Ottoman rule by the Russian army. It remained within the borders of Bulgaria until July of the same year, when it became the capital of the autonomous Ottoman region of Eastern Rumelia. In 1885, Plovdiv and Eastern Rumelia joined Bulgaria. Plovdiv is situated in a fertile region of south-central Bulgaria on the two banks of the Maritsa River. The city has historically developed on seven syenite hills, some of which are high. Because of these hills, Plovdiv is often referred to in Bulgaria as "The City of the Seven Hills". Plovdiv is host to cultural events such as the International Fair Plovdiv, the international theatrical festival "A stage on a crossroad", and the TV festival "The golden chest". There are many remains preserved from antiquity such as the ancient Plovdiv Roman theatre, Roman odeon, Roman aqueduct, Roman Stadium, the archaeological complex Eirene, and others. The oldest American educational institution outside the United States was founded in Plovdiv in 1860, which was later moved to Sofia – todays American College of Sofia. On 5 September 2014, Plovdiv was selected as the Bulgarian host of the European Capital of Culture 2019. This happened with the help of the http://plovdiv2019.eu/en/ Municipal Foundation "Plovdiv 2019″ - a non-government organization which was established in 2011 by Plovdivs City Council. The main objectives were to develop and to prepare Plovdivs bid book for European Capital of Culture in 2019. The organization has a board of directors, which consists of 9 members and an Executive Director. The foundation also has a Public Council, chaired by the mayor of the city, and a Control Board supervises the organizations activities. The main objective of the foundation is strategic development and implementation of the bid book.