Betsy began her career in international finance and it has since grown into a comprehensive approach to journalism as she's been able to tap into that experience along with her time spent in academia ...

Want more charts like these? See our charts on the secrets of the jobless recovery, the richest 1 percent of Americans, and how the superwealthy beat the IRS. How Rich Are the Superrich? A huge share ...

A version of this story appears in the September 2020 issue of National Geographic magazine. Philadelphia detected its first case of a deadly, fast-spreading strain of influenza on September 17, 1918.