Trajan’s Column, completed in 113CE, is a masterpiece of Roman art and engineering. It has stood for more than 1900 years intact as the rest of the Roman Forum crumbled around it. The tower comprises 29 blocks of solid marble each weighing from 29-77 tons. Each marble drum had windows and a staircase allowing access to the top pulled into place by an elaborate pulley system. Watch this stop-motion video by National Geographic on how it was made in ancient times. For even more insight, watch the artists’ making-of video.