The rise of port cities saw the clustering of populations caused by the development of steamships and railroads. Urbanization increased from 1700 to 1922, with towns and cities growing. Improvements in health and sanitation made them more attractive to live and work in. Port cities like Salonica, in Greece, saw its population rise from 55,000 in 1800 to 160,000 in 1912 and İzmir which had a population of 150,000 in 1800 grew to 300,000 by 1914. Some regions conversely had population falls – Belgrade saw its population drop from 25,000 to 8,000 mainly due to political strife.