After four previous editions Complexity Fest returns for the fifth time to all halls of Patronaat Haarlem on the 15th of February 2020 with a special pre-party the day before, February 14th.

Complexity Fest is an indoor festival that is all about adventurous and boundary pushing heavy music. After the most diverse acts have graced the stage of Complexity, the festival is once again looking to outdo themselves with a surprising and eclectic rollercoaster ride of a line-up.