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 (also known in the U.K. as the Great Slump) was a dramatic, worldwide economic downturn beginning in some countries as early as 1928. The beginning of the Great Depression in the United States is associated with the stock market crash on October 29, 1929, known as Black Tuesday. The depression had devastating effects in both the industrialized countries and those which exported raw materials. International trade declined sharply, as did personal incomes, tax revenues, prices and profits.