A federal city is a city which is a separate entity. It has a status of both: an inhabited locality and a federal subject.
There are three federal cities in Russia: Moscow, Saint Petersburg and Sevastopol in the disputed region of Crimea.
<em>All three cities have federal importance and federal power.</em> Parts of those cities are highly important government/military areas with very restricted settlements rights.
The federal power is seen most in federal representation. A federal city has its own members in the Federal Council, its own legally elected legislature and elected/appointed executive authority. A federal city can create its own laws, has its own taxation power and the power to subdivide the city in smaller municipalities. It has many special privileges which ordinary cities don't.
The British Army during the American Revolutionary War served for eight years in campaigns fought around the globe. Defeat at the Siege of Yorktown to a combined Franco-US force ultimately led to the loss of the Thirteen Colonies in eastern North America, and the concluding Treaty of Paris deprived Britain of many of the gains achieved in the Seven Years' War. However several victories elsewhere meant that much of the British Empire remained intact.
Craftsman left their managers and made specific shops. It likewise separates the craftsman class into independently employed skilled workers and blue-collar specialists. Joblessness ascended in the 1820s while subsidence and frenzy in the year 1837.
The wall separated East Berlin and West Berlin. It was built in order to prevent people from fleeing East Berlin. In many ways it was the perfect symbol of the "Iron Curtain" that separated the democratic western countries and the communist countries of Eastern Europe throughout the Cold War.