You could spend years trying to read Walter Benjamin's The Arcades Project--after all, he spent much of the last 13 years of his life doing the research. When he committed suicide in 1940, he destroyed his copy of the manuscript, and so for decades the work was believed lost. But another copy turned up, and Howard Eiland and Kevin McLaughlin have translated it into English.
It is a complex, fragmentary work--more a series of notes for a book than a book itself--which probes the culture of the Paris arcades (a cross between covered streets and shopping malls) of the mid-19th century and the flaneur ("the man who walks long and aimlessly through the streets" in an "anamnestic intoxication [that] ... feeds on the sensory data taking shape before his eyes but often possesses itself of abstract knowledge--indeed, of dead facts--as something experienced and lived through"). The Arcades Project is, frankly, so dense a work that one hardly has enough time to glimpse fleetingly at its sections--over 100 pages of notes on Baudelaire alone!--before mentioning it to you, though one certainly looks forward to the opportunity to peruse it at leisure.