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.
Overview: Causes of the Great Depression. The crash of the New York Stock Exchange on October 29, 1929, signaled the start of the Great Depression, the worst economic crisis in U.S. history. This period would last until 1941, when the United States began preparations to enter World War II (1939â45).