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.
Although a common belief is that the Great Depression was triggered by the 1929 crash of the stock market, the stock market in 1929 had reached record fundamental valuations in spite of deteriorating economic conditions such as rising unemployment, overproduction (excess capacity), underconsumption and high debt.