You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Estonian_language

Context:
During the Perestroika era, The Law on the Status of the Estonian Language was adopted in January 1989. The collapse of the Soviet Union led to the restoration of Republic of Estonia's independence. Estonian went back to being the only state language in Estonia which in practice meant that use of Estonian was promoted while the use of Russian was discouraged.

Question:
What historical event once again freed Estonia?

collapse of the Soviet Union