The ATP Tour is the top professional men's tennis circuit organized by the Association of Tennis Professionals (ATP), featuring a series of tournaments held around the world. Established in 1990, it includes a variety of events such as the ATP Masters 1000, ATP 500, and ATP 250, culminating in the ATP Finals, which showcases the top eight players of the season. The tour provides a structured ranking system, allowing players to accumulate points based on their performance, which influences their standings and eligibility for major tournaments.