Conversation so far:
does an australian passport holder need a visa for spain
Australian citizens traveling to the E.U. will require a visa waiver for Europe from Australia as of the end of 2022.
when did spain become a member state of the schengen area
Spain and Portugal joined the Schengen Agreement on 25th June 1991

Question: when was the agreement signed
Self-contained rewrite: when was the schengen agreement signed