What was the biggest commonality for all of the banking crises of the 20th and 21st centuries?

Banking panics, which is the basis for financial crises and banking crises of 20th and 21st centuries.

Explanation:

A banking panic is a financial term often referred to as bank panic, it describes a financial crisis that occurs as a result of many bank customers suddenly wanting to convert their threatened deposits into cash or totally withdraw all their cash deposit out of their domestic banking system altogether.

Unlike Bank run that affect single bank, bank panic affects many banks together, thereby leading to systemic banking crises, in which a country experiences many defaults, hence, many financial institutions and corporations face great difficulties repaying contracts

Hence, due to economic recession that occurred in the 20th century and recently occurred in 21st century, bank panic has been the resulting effects, leading to major financial banking crises.

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.

answer:

it caused mass african migration, african populations to grow, african empires to topple, and racism against slaves to emerge.