Thinking big has brought humanity ambitious, monumental feats of architecture — from the elegance of the Taj Mahal in India to the Burj Khalifa in Dubai, the world’s largest structure. But many others haven’t made it out of the blueprint phase. The World’s host Carol Hills hears from Sam Lubell, the co-author of the “Atlas of Never Built Architecture,” a compendium of buildings that were designed, but never got off the ground.