All the leagues are bound together by the principle of promotion and relegation. Clubs that are successful in their league can rise higher in the pyramid, whilst those that finish at the bottom can find themselves sinking further down. In theory it is possible for a lowly local amateur club to rise to the pinnacle of the English game and become champions of the Premier League. While this may be unlikely in practice, there certainly is significant movement within the pyramid. The number of teams promoted between leagues or divisions varies, and promotion is usually contingent on meeting criteria set by the higher league, especially concerning appropriate facilities and finances.