★"This great STEAM offering has multiple applications and will be useful for report writers and aspiring architects alike."--Booklist, starred review ★"Finely detailed inside and outside...Broad in scope, perceptively organized, and enriched with fascinating entries."--Kirkus Reviews, starred review Why did they build it so high? People have been constructing tall buildings for thousands of years, for many different reasons. Castle walls kept people safe. Utility towers transmit TV and cell-phone signals. Observatories give people a bird's-eye view of the world. Beautiful buildings stand out in the crowd. Skyscrapers provide housing for a lot of people. There are some good reasons for building up, and a few bad ones as well. With a growing global population, we will need more and more space to live, learn and work in. But what does that mean for the health of the planet? Can we do it sustainably? Tall buildings may be part of the answer. From the Great Pyramids of Giza and the Leaning Tower of Pisa to the Burj Khalifa and the Shanghai Tower, Why Humans Build Up asks why and how we build higher and higher, and what that means for the planet.