The AFC Champions League in Asian clubs is just like the UEFA Champions League in European clubs. This league, hosted by the AFC(Asian Football Confederation) and in normal circumstances, it is played by 28 Asian clubs along with the league defending Champions.
The league started in 1967 as the Asian Champion Club Tournament. And as a start, it had been played by eight(8) domestic champions from eight Asian leagues who competed in the inaugural season. With the exception of 1968 season, the tournament was held annually until 1971. During this first four editions, two Israeli clubs from Tel Aviv took three championships. But in 1972, due to lack of interests, the tournament was canceled which eventually resulted in withdrawals of most participants except for two clubs. The tournament was not held for next fourteen years. This also due to the fact that professionalism in Asian club football did not start till late 90s and early 2000s. The price money for this league is $600,000 for the winner and $400,000 for the runner up. 2007's champion was the Urawa Red Diamonds of Japan who won 3-1 against Sepahan of Iran.
Some facts were taken from: WikiPedia.com