Novosibirsk
Novosibirsk is the largest city in Siberia, which is made up of about a dozen different administrative districts.
Whan it has a seat----------------A City is a City when it is INCORPORATED....essentially, it then becomes a Buisness It makes money through taxes (property, Sales, etc.) otherwise, an area not...
Both which and what can be used
A city is a city because it was one the the important places in the world.