Amazon wants to build a second headquarters, and it’s invited U.S. cities to make an offer. Cities are falling over themselves in some cases, with promises of tax breaks and other incentives. Amazon’s HQ2, as it’s called, is expected to bring 50,000 new jobs and billions of investment dollars. But there will undoubtedly be downsides. We look at how Amazon has changed Seattle, and whether politicians have a conflict of interest when they try to woo Amazon, and regulate it