Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

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.

Simply sign up to the Global Economy myFT Digest -- delivered directly to your inbox. The FT global inflation and interest rates tracker provides a regularly updated picture of consumer price ...

Chocolate or strawberry? Life or death? We make some choices quickly and automatically, relying on mental shortcuts our brains have developed over the years to guide us in the best course of action.