There have been two very popular stock market bubbles in the twentieth century which ended in a crash. The first one was the boom and bust of the 1920s which saw the U.S. stock market soar to great heights. The crash came with the Great Depression in 1929. The more recent one was the dot-com bubble that ended with the bubble bursting at the turn of the millennium.

Both these stock market bubbles were attributed to the technological innovations that were introduced during the period with the 1920s seeing the advent of automobiles and radio among other household items. In the 1990s, it was the internet boom and the rapid growth of e-commerce and related technologies.

One thing that investors should be warned about is that in these bubbles investment tends to flow towards speculative areas rather than businesses that are actually great for the long haul and have solid value.