The Critical Decentralisation Cluster on the Chaos Communication Congress (36C3) is an area and grouping of similar minded projects, which are offering workshops and host a space to critically discuss the future of decentralisation.
The cluster consists of a recording stage as well as workshop areas for the assemblies and similar minded groups and projects. Part of the cluster is a coffee area from Paralelni Polis, as well as lots of space to hack, work, and learn.
The Chaos Computer Club (CCC) is the largest (and oldest) hacker association in Europe and was founded in 1981. The annual Chaos Communication Congress takes place end of the year, since 1984. It is considered one of the largest (over 15,000 attendees) events of this kind, alongside the DEF CON in Las Vegas.