The Erlang language and system was designed around a set of requirements for telecom systems. They were distributed, massively concurrent systems which had to scale with demand, be capable of handling massive peak loads and never fail. The Erlang concurrency and error-handling model was developed around these requirements. This talk will describe the development of the language and the design of systems based on the Erlang. It will also look at the further development with the introduction of new languages in the Erlang environment - the Erlang ecosystem.