The ATP World Tour comprises ATP World Tour Masters 1000, ATP World Tour 500 series, ATP World Tour 250 series and ATP Challenger Tour. The ATP tour also oversees the ATP Champions Tour for seniors. Grand Slams (as well as the Olympic Tennis Tournament and Davis Cup) do not fall under the auspices of the ATP. In these events, however, ranking points are awarded. Players and doubles teams with most ranking points (collected during the calendar year) play in the season-ending ATP World Tour Finals, which, from 2000-2008, was run jointly with the International Tennis Federation (ITF). The week-long introductory level Futures tournaments are ITF events and they count towards ATP Entry Ranking. The four-week ITF Satellite tournaments were discontinued in 2007. Grand Slam tournaments are overseen by the ITF and they count towards the players' ATP rankings.