Algol 60 was an interesting language in many respects. It is the mother of nearly all imperative programming languages existing today; it had no data structures, just scalars and arrays; but it introduced block structure and scoping rules; and it was the first language specified using the Backus-Naur-Form (BNF) which is still in use today. I recently wrote a parser for it (on my way to a Simula 67 compiler): https://github.com/rochus-keller/Algol60.
