Moar - This page needs 'Moar' work, it may have been copy-pasted or just is really not up to standard.
Architecture
City 17 is located somewhere in the Eastern Europe. The buildings has old Eastern Europe architecture from the World War II, but also different styles from the 70's, 80's and 90's.
When the Combine came, they started building new buildings out of black/blue metal. Some buildings can be seen completely redone, while others are untouched. The city is said towards the beginning of Half life 2 to be Dr.Breen's base of operations, which means this is the city where Breen resides inside the Citadel, it is unknown why Dr.Breen would have chosen City 17 above all other remaining urban centres still remaining on earth.
The City
Several Breencasts have been placed throughout the city to adress the Citizens about what's happening. And in the middle of the city is the Citadel, a giant skyscaper, which serves as the Combine's headquarter, and Breen's office.