JANUARY 23, 2020: The city of Wuhan -- the location that the virus originated -- is placed under quarantine.
JANUARY 30, 2020: The World Health Organization declares the COVID-19 a public-health emergency.
JANUARY 31, 2020: United States President Donald Trump bans non-American citizens from entering the United States if they had been in China the prior two weeks.
MARCH 11, 2020: The longest-running bull market came to an abrupt end after the Dow Jones Industrial Average dropped more than 1,400 points. The U.S. entered its first bear market since the 2008 financial crisis.
All images from iStock.