Across the globe, radical architects, ingenious engineers, and skilled builders are creating structures so outrageous, they defy logic...and often even gravity. From a Manhattan skyscraper that looks like a Jenga tower to a Singapore glass dome big enough to house a mountain to a high rise in Italy with a built-in forest, we examine the world's most extraordinary buildings, bridges, and lifts, reveal their design secrets, and discover the incredible stories of their construction as we try to answer the question: How Did They Build That?