The internet can be broadly divided into three parts: surface, deep and dark. The dark web has become notorious in the media for being a hidden part of the web where all manner of illegal activities take place. This review investigates how the dark web is being utilised with an emphasis on cybercrime, and how law enforcement plays the role of its adversary. The review describes these hidden spaces, sheds light on their history, the activities that they harbour – including cybercrime, the nature of attention they receive, and methodologies employed by law enforcement in an attempt to defeat their purpose. More importantly, it is argued that these spaces should be considered a phenomenon and not an isolated occurrence to be taken as merely a natural consequence of technology. This paper contributes to the area of dark web research by serving as a reference document and by proposing a research agenda.