In fact, Morningstar research looks all the way back to the 1870s and says that a dollar invested then in a hypothetical U.S. stock index would today be worth more than $28,000 -- even after going through 19 market crashes.

Stocks have rallied hard for most of this week, as investors have grown less pessimistic about both President Trump's tariff war and the risks to central-bank independence. Here is a breakdown of how the market has bounced since Monday.