Porto and Benfica have been the dominant forces of Portuguese football and when they meet, the country stops, knowing that their clashes often define the outcome of the silverware in that campaign. The clubs have shared virtually every title of the past two decades, and there has been an ebb and flow to proceedings, with Benfica virtually owning the 60s and 70s before Porto begun to emerge as a genuine challenger in the mid-1980s. Their competition comes from Lisbon and Porto being the largest two populations centres in Portugal, meaning their fan bases are huge and, with Sporting, also based in Lisbon, control the football landscape to a significant degree. These days the derby is often attended by numerous scouts from across Europe, as the match has been a breeding ground for exceptional talent that has moved onto bigger clubs.