During his campaign for the presidency, one of Donald Trumpâs signature promises was that he would build a âgreat great wallâ on the border between the United States and Mexico, and Mexico was going to pay for it. A year and a half into his term, with only a few prototype segments erected, the wall is the 2,000-mile multibillion-dollar elephant in the room of contemporary American life. In The Great Great Wall, architectural historian and critic Ian Volner takes a deep dive into the story of Trumpâs wall. Volner follows the conception, selling, design, and construction (or lack thereof) of this expensive and consequential barrier, giving listeners a detailed description of whatâs happening in Washington, DCâand along the border. He also travels far afield, to China, the Middle East, northern England, and back to our border to examine the barriers weâve been building for centuries. Why do we build walls? What do they reveal about human history?