While earlier versions existed, James Watt’s perfection of the steam engine in 1776 was the primary catalyst for the Industrial Revolution. By adding a separate condenser, Watt vastly increased the engine's efficiency, allowing it to power factories, mills, and later, locomotives and steamships. This invention decoupled human productivity from the limitations of animal and human muscle or the geography of fast-flowing rivers. It led to the rise of the factory system, mass production, and a massive migration from rural areas to burgeoning industrial cities. The steam engine essentially 'shrank' the world by making travel and transport faster and more reliable than ever before. However, it also initiated the large-scale burning of fossil fuels, particularly coal, marking the beginning of the significant human impact on the Earth’s atmosphere and climate that continues to this day.