Two months in a wrong country
Back in 1831, a young French gentleman took a boat to New York, planning to study American penal institutions. He spent nine months in the States of North America, met people from various walks of life and in due course published two volumes of what an encyclopedia of American life. Several years after Tocqueville's American journey, an older French aristocrat stayed in Russia for two months and produced another influential book. I am talking about Astolphe de Custine and his Russia in 1839. George Kennan found it prophetic; Theodore Dalrymple based a book on it; Alexandr Sokurov (the film director) centered The Russian Ark around a Custine-like figure.
Russia in 1839 was banned under Nicholas I, ensuring that every Russian with enough French would read it. Critical analyses followed (oh, the pleasure of criticizing a banned book!), and those familiar with the history of 19th century Russia will probably find plenty of anecdotes passing as facts and fiction passing as truth in Custine's book. Custine's ideological opponents might even want to compare his collection of letters not to Tocqueville's writings but to Knut Hamsun's.
This said, Custine -- from his first letter home -- comes out as character I can't help liking...