"In a way, our study of one cross-section of the city represented a synecdoche, taking a small part of London as a whole."
A synecdoche is a figure of speech meaning a word used to represent a whole. For instance, the headline "England won by six wickets" uses England to mean 'the English cricket team'. It comes from the Greek syn 'together' and ekdoche 'interpretation'.
Victor Hugo's Les Miserables contains one of the longest SENTENCES in the French language -- 823 words without a full stop