Which major city is the only commercially significant wine region unto itself?

B.

Answer: B. Vienna, located along the Danube River in northeastern Austria, is the only major city in the world that is a commercially significant wine region. Within the city limits there are over 1,700 acres of grapes, of which about 85% are dedicated to white grape varietals. All vines fall under a government protection program lest developers be tempted to put such valuable real estate to more profitable uses.