7857
Before the urbanization of the 20th century occurred , select ruins of the Roman-era city could be seen , most prominently sections of the Roman defensive walls which surrounded the city and multiple aqueducts which once supplied Nicomedia 's water .
 location: Nicomedia
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 location: Nicomedia