At the dawn of our final Period (4) of Study, we see the end of land based and maritime empires (period 2) and start with the shifts are making through revolution.
The West dominated the global political order at the beginning of the 20th century, but both land-based and maritime empires gave way to new states by the century's end.
The older, land-based Ottoman, Russian, and Qing empires collapsed due to a combination of international and external factors. These changes in Russia eventually led to communist revolution.
States around the world challenging the existing political and social order, including the Mexican Revolution that arose as result of political crisis.