Founded in 1836, Houston is now the country's fourth-largest city. In the early 20th century, Houston's economy shifted from agriculture to oil, fueling the city's explosive growth in the following decades. Houston grabbed the reins and saw a building boom in commercial, residential, and civic architecture redefine the city and skyline. Modernism was a new and fresh architectural expression and the perfect complement to the city's can-do entrepreneurial spirit. The 1960s brought ground-breaking ceremonies for the National Aeronautics and Space Administration's (NASA) headquarters, while residents and tourists alike lined up to tour the revolutionary new Astrodome. Building Modern Houston tells the story of Houston's architecture during its transformation from "Bayou City" to "Space City."