Title: 2020s in economic history
Content:  The 2020 stock market crash was a major and sudden global stock market crash that began on 20 February 2020 and ended on 7 April. The crash was the fastest fall in global stock markets in financial history and the most devastating crash since the Wall Street Crash of 1929. The crash, however, only caused a short-lived bear market, and in April global stock markets re-entered a bull market, which would continue until late October of that year.
Title: Stock market
Content:   A stock market crash is often defined as a sharp dip in share prices of stocks listed on the stock exchanges. In parallel with various economic factors, a reason for stock market crashes is also due to panic and investing public's loss of confidence. Often, stock market crashes end speculative economic bubbles. There have been famous stock market crashes that have ended in the loss of billions of dollars and wealth destruction on a massive scale. An increasing number of people are involved in the stock market, especially since the social security and retirement plans are being increasingly privatized and linked to stocks and bonds and other elements of the market. There have been a number of famous stock market crashes like the Wall Street Crash of 1929, the stock market crash of 1973–4, the Black Monday of 1987, the Dot-com bubble of 2000, and the Stock Market Crash of 2008.
Title: Wall Street Crash of 1929
Content:  The Wall Street Crash of 1929, also known as the Great Crash, was a major American stock market crash that occurred in the autumn of 1929. It started in September and ended late in October, when share prices on the New York Stock Exchange collapsed. It was the most devastating stock market crash in the history of the United States, when taking into consideration the full extent and duration of its aftereffects. The Great Crash is mostly associated with October 24, 1929, called Black Thursday, the day of the largest sell-off of shares in U.S. history, and October 29, 1929, called Black Tuesday, when investors traded some 16 million shares on the New York Stock Exchange in a single day. The crash, which followed the London Stock Exchange's crash of September, signaled the beginning of the Great Depression.
Title: 2010 flash crash
Content:   The May 6, 2010, flash crash, also known as the crash of 2:45 or simply the flash crash, was a United States trillion-dollar stock market crash, which started at 2:32 p.m. EDT and lasted for approximately 36 minutes.
Title: 2020 stock market crash
Content:  Though the crash began on 20 February, selling was intensified during the first half of March to mid-March. During the crash, there were multiple severe daily drops in the global stock market, the largest drop was on 16 March, nicknamed 'Black Monday II' of 12–13% in most global markets. There were two other significant dates of crashes in the stock markets, one being 9 March, nicknamed 'Black Monday I', and on 12 March, nicknamed 'Black Thursday'. To deal with the panic, banks and reserves across the world cut their interest rates, bank rates and cash flow rates, as well as offering unprecedented support to investors and markets.
Title: Stock market
Content:  One of the most famous stock market crashes started October 24, 1929, on Black Thursday. The Dow Jones Industrial Average lost 50% during this stock market crash. It was the beginning of the Great Depression.
Title: 2020 stock market crash
Content:  its most recent peak, while the BSE SENSEX on the Bombay Stock Exchange fell 2,919 (or 8.18%) to 32,778. The benchmark stock market index on the Johannesburg Stock Exchange fell by 9.3%. The MERVAL on the Buenos Aires Stock Exchange fell 9.5% to 19.5% on the week. 12 March was the second time, following 9 March drop, that the 7%-drop circuit breaker was triggered since being implemented in 2013. In Colombia, the peso set an all-time low against the U.S. dollar, when it traded above 4000 pesos for the first time on record. The Mexican peso also set an all-time record low against the U.S. dollar, trading at 22.99 pesos.
Title: 1973–1974 stock market crash
Content:  The 1973–1974 stock market crash caused a bear market between January 1973 and December 1974. Affecting all the major stock markets in the world, particularly the United Kingdom, it was one of the worst stock market downturns since the Great Depression, the other being the financial crisis of 2007–2008. The crash came after the collapse of the Bretton Woods system over the previous two years, with the associated 'Nixon Shock' and United States dollar devaluation under the Smithsonian Agreement. It was compounded by the outbreak of the 1973 oil crisis in October of that year. It was a major event of the 1970s recession.
Title: 2020 stock market crash
Content:  their most recent peaks on 19 February in Copenhagen and on 21 February in Tallinn and Vilnius. The Dow Jones Industrial Average, the NASDAQ Composite, and the S&P 500 all fell by 12–13%, with the Dow eclipsing the one-day drop record set on 12 March and the trading curb being activated at the beginning of trading for the third time (after 9 and 12 March). Oil prices fell by 10%, while the yields on 10-year and 30-year U.S. Treasury securities fell to 0.76% and 1.38% respectively (while their yield curve remained normal for the third straight trading session). The CBOE Volatility Index closed at 82.69 on 16 March, the highest ever closing for the index (though there were higher intraday peaks in 2008). Around noon on 16 March, the Federal Reserve 
Title: Black Monday
Content: 28 October 1929 – Stock markets in the United States began to crash as part of the Wall Street Crash of 1929. ; 19 October 1987 – Black Monday (1987) Stock markets around the world crashed, shedding a huge value in a very short time. ; 29 September 2008 – Great Recession. Following the bursting of the Real estate bubble and the Financial crisis of 2007–08, stock markets worldwide crashed, leading to the Great Recession. ; 8 August 2011 - Black Monday (2011): A stock market crash from a credit rate downgrade of the United States' debt. ; 24 August 2015 – 2015 

Question: when was the last time stock market crashed?
Answer: 27 Oct 1997.
18 August 2015.