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.
The Great Depression was a long and extensive economic crisis, affecting most developed nations in the early and mid 1930s. It was triggered by a stockmarket crash in New York City in 1929, then soon spread beyond the United States, crippling the economies of dozens of nations.