Throughout the years, a number of teams in the National Football League (NFL) have either moved or merged. In the early years, the NFL was not stable and teams moved frequently to survive, or folded only to be resurrected in a different city with the same players and owners, while the Great Depression era saw the movement of most surviving small-town NFL teams to larger cities to ensure survival, and franchise mergers were also popular during World War II in response to the exodus of players to war service. Few, if any, of these relocations and mergers were accompanied with widespread controversy. Franchise moves became far more controversial in the late 20th century when a vastly more popular NFL, free from financial instability, allowed many franchises to abandon long-held strongholds for perceived financially greener pastures. Despite a Pete Rozelle promise to Congress not to relocate franchises in return for a law exempting the league from certain aspects of antitrust laws, thus making possible the AFL–NFL merger, several franchises have relocated since the merger and the passage of the law (Public Law 89-800) which sanctioned it. While owners invariably cited financial difficulties as the primary factor in such moves, many fans bitterly disputed these contentions, especially in Baltimore, St. Louis, and Cleveland, each of which eventually received teams some years after their original franchises moved. However, Los Angeles, the second-largest media market in the United States, did not have an NFL team from 1995 to 2015. The league had started actively promoting a return to Los Angeles no later than 2006, and in January 2016, the NFL gave the St. Louis Rams approval to move back to Los Angeles. A year later, the Chargers also relocated to the city, while the Raiders relocated to Las Vegas in 2020. Within the United States, the San Diego–Tijuana market is currently the largest metropolitan area (and only one with over 3 million residents) without an NFL franchise. The only other city to be seriously considered in the country in recent times was San Antonio, Texas, which the Raiders seriously considered as a relocation candidate in 2014 before choosing Las Vegas. Speculation on future relocation has mainly been centered around two larger cities outside the United States: Toronto, Canada (q.v. National Football League in Toronto) and London, England, United Kingdom (q.v. Potential London NFL franchise), the latter of which would be the first attempt by