This computer history timeline infographic depicts the early nineteenth-century designs that changed the world in the twentieth century. Computers have been around for over two hundred years. Initially theorized by mathematicians and entrepreneurs, mechanical calculating machines were designed and built during the nineteenth century to solve increasingly complex number-crunching challenges. By the early twentieth century, technological advancement had enabled ever-more-complex computers, and computers had grown larger and more powerful. Computers today are almost unrecognizable from designs from the nineteenth century, such as Charles Babbage's Analytical Engine, or even from the massive computers of the twentieth century, such as the Electronic Numerical Integrator and Calculator.