The Aerial Valley (1810) proves that a utopian society can only maintain stability if it remains technologically limited and isolated from outside influences; it is a sensitive challenge to the philosophy of progress as an instrument of perfectibility. The Year 2800 (1829) bases its anticipations of future improvement on bold social reforms. Paris in Dreams (1863) echoes the then-ongoing endeavors of Baron Haussmann, who was busy remodeling the city in accordance with his own utopian design. Victor Hugo's The Future was the first chapter of the great author's introduction to a guide-book produced for visitors to the Exposition Universelle of 1867. Gustave Marx's Love a Thousand Years Hence (1889) is a satire of the glut of utopian accounts of future Paris, being elevated to the capital of a unified Europe.