100 Places To See In Your Lifetime-Heaven On Earth#22-Great Wall Of China-"The largest man-made thing on earth, it stretches like a palpable dragon for somewhere between 1,678 miles and 6,214 miles, depending how you measure it. There are loops and, in places, quadruple walls. By any measure it is one incredible barrier, nearly 20 feet wide at the base and 30 feet high. The Great Wall figures heavily in Chinese art and mythology."