The global one is much more interesting; showing first the rise of rome, and then of various other cultural centers in Europe which start becoming increasingly intense blobs of light as the modern age begins; crossing the atlantic, and then both N-America and Europe exploding in color as the 20th century arrives. It's predictable but still interesting to see that the brightest centers on both continents tend correspond to the most highly developed urban centers and regions. It's also cool how can you see exactly where and when various cultural/scientific revolutions take place: Ancient Rome, The spread to the Frankish realm after the empire collapses, the rest of Europe catching up as the Frankish empire collapses into France and the HRE, The renaissance in Northern Italy and Flanders followed by the sudden scientific/artistic dominance of Holland which then gets slowly overtaken by England and Paris, and finally the rise of the German industrial superpower. Pretty cool.