Originally the site of an ancient settlement, the town was first built at the north side of a natural harbour. By the 16th century, the walled town had been further fortified by successive rulers into a massive medieval castle, the "Kastro". The current town has expanded out from the Kastro, and the port in the last 200 years. After the devastating earthquake of 1881, the town was substantially rebuilt in neoclassical style, although much of the quayside and outskirts are more modern. Although the population is relatively stable, the town continues to expand with suburbs being built to the north and south. Nevertheless, the centre of the town is still concentrated between the port and castle where the administration, several museums, the main shopping street "Aplotaria", and the municipal gardens lie.North of Chios lies the suburb of Vrontados, while the Chios Island National Airport and town of Karfas lie a few kilometres south of the centre.