The Rams joined the Lakers, Dodgers, Sparks, Galaxy, and Kings as Los Angeles pro teams to have been crowned in the last eight years. This makes the Californian city the most successful sportingly speaking in the United States in the last decade.
There are nine championships that Los Angeles has achieved in the main sports leagues in the country. In the NFL, this city had not won since 1984, while in the MLB the Dodgers had not won a title since 1988.
Other cities in the United States have won a few titles, but it's usually in the same sport. This is the case of New England; they won three championships with the Patriots in the NFL and Boston that won two championships with the Red Sox in the MLB, among others.