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.
Together, the 1929 stock market crash and the Great Depression formed the largest financial crisis of the 20th century. The panic of October 1929 has come to serve as a symbol of the economic contraction that gripped the world during the next decade.