In pictures: Solidarity in Poland:

In 1978 a Polish archbishop, Karol Wojtyla, was elected Pope taking the name John Paul II. His return a year later was a triumphal progress in front of millions.

The strength of Catholicism in Poland was vital for the development of the strikes. Through it, Poles were able to assert their solidarity en masse and in public.

Walesa said that he "demonstrated how numerous we were. He told us not to be afraid."

Here Pope John Paul II embraces Walesa in Gdansk, in June 1987.