D.C. United is an American professional soccer club based in Washington, D.C. which competes in Major League Soccer (MLS). It is one of the ten charter clubs of MLS, having competed in the league since its inception, in 1996. Over the club's history, D.C. United has been considered to be the flagship franchise of MLS, having won 12 international and domestic titles or honors. Domestically, United has been one of the most successful MLS clubs. United has won the U.S. Open Cup twice, and holds an MLS record for most MLS Cup and Supporters' Shields apiece, winning each honor four times. United was also the first club to win both the MLS Cup and MLS Supporters' Shield consecutively. On the international stage, D.C. United has competed in both the CONCACAF Champions League and its predecessor, the CONCACAF Champions' Cup.