Cnidaria is a phylum within Kingdom Animalia which consists of hydras, jellies (or jellyfish), sea anemones, and corals. All cnidarians are radially symmetrical, and there are two main radially symmetrical body types.
The stock market crash, on black Tuesday (October 29, 1929) began the Great Depression.
On Black Tuesday, October 29, 1929, the stock market crashed, triggering the Great Depression, the worst economic collapse in the history of the modern industrial world. It spread from the United States to the rest of the world, lasting from the end of 1929 until the early 1940s.