This release encouraged Opeth to go on their first world tour , headlined Europe and playing to a crowd of 60,000 at the 2001 Wacken Open Air festival in Germany . In support of Blackwater Park , Opeth embarked on its first world tour , headlined Europe for the first time , and made an appearance at the 2001 Wacken Open Air festival in Germany , playing to a crowd of 60,000 .