What is gulag archipelago?

Some articles on gulag archipelago, gulag:

The Gulag Archipelago - Historical Impact of The Text
... With The Gulag Archipelago, Lenin's political and historical legacy became problematic, and the fractions of Western communist parties who still based their economic ... diplomat, called The Gulag Archipelago, "the most powerful single indictment of a political regime ever to be levied in modern times." In an Interview with German weekly Die Zeit British historian Orlando Figes ... Thus, he claims "The Gulag Archipelago spoke for a whole nation and was the voice of all those who suffered" ...
Russian Political Jokes - Soviet Union - Gulag - Gulag Archipelago
... Alexander Solzhenitsyn's book, Gulag Archipelago, has a chapter entitled "Zeks as a Nation", which is a mock ethnographic sketch intended to "prove ... water into a cup, a typical retort was "The prosecutor will add!" "Is it hard in gulag?" — "Only during the first 10 years." When the quarter-century term had become standard for ...