China's fast-growing megacities -- 43 cities of one-million-plus today, and a projected 221 by 2025 -- may at first blush look homogenous and interchangeable, but of course a metropolis is more than a collection of buildings, and foundations aren't only poured in concrete. With few exceptions, China's most significant modern metropolises have varied, lengthy, and winding histories. At a recent literary event in Beijing, the author and New Yorker contributor Zha Jianying was asked to explain if and how "history and modernity coexist" in China. Zha, who publishes in both Mandarin and English and is one of today's most insightful writers in explaining China to the West, and vice-versa, mused: "It depends on what history you care about. People care about living history -- the language, the cuisine. But architecture?" She paused. "Every new dynasty would burn the old palace and build anew. It's very different in that sense than Europe ... There's a long venerable history of destroying the old."