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 global economic crisis that may have been triggered by political decisions including war reparations post-World War I, protectionism such as the imposition of congressional tariffs on European goods or by speculation that caused the Stock Market Collapse of 1929.