Big History is an approach to world history that takes as its subject the story of the whole of the Universe, from its creation, 13.8 billion years ago, in the Big Bang. It describes the creation of stars, the forging of new types of matter in dying stars, the formation of the first planets and moons, and the emergence of life on at least one planet, the Earth.

Oceans, which cover approximately 70 percent of the earth’s surface, have played a crucial role in shaping human history. Using oceans and seas as a unit for analysis is, however, a relatively new framework for historical analysis. The traditional units of historical analysis include civilizations, continents and especially nation-states.

Environmental history lends itself particularly well to a world history framework. Environmental processes do not limit themselves to national or cultural borders. The climate, for example, has always been a global system. Environmental history may also consist of unusual sources and feature "archives" that exist in the natural world.

World history courses often feature the rise and fall of various empires, but often little attention is paid to the concept of empire itself.