At first, American and European open-wheel racing were not distinct disciplines. Races on both continents were mostly point-to-point races, and large ovals tracks emerged on both continents. But in America, racing took off at horse-race tracks and at the Indianapolis Motor Speedway, while in Europe, racing from point to point and around large circuits gained in popularity. Grand Prix racing (which became Formula One) and rally racing then diverged in Europe. Formula One was established after World War II as the World Championship for road racing, and F1 cars became increasingly specialized and high-tech.