Self-driving cars are coming. When exactly will they arrive? Well that’s a question nobody has the answer to, but it might be sooner than you think.

The amount of money companies are investing in self-driving cars is through the rooftop. For example, Ford just invested $1 billion in Argo AI, a startup founded by former Google and Uber employees. The advancement of self-driving car technology has been incredible the past few years, but the idea itself of a self-driving car isn’t a novel idea; there were plans for self-driving cars in the 1920s.

Toyota: Fully Autonomous Cars Not Even Close

The Boston Consulting Group predicts that from 2025-2035, the market for partially and fully autonomous vehicles is expected to grow between $42 billion and $77 billion. Before looking ahead, however, it’s always fun to take a look back at how things started.

The folks at GetoffRoad put together the following infographic that does a nice job rounding up the state of self-driving cars, including a timeline of self-driving car developments, a look at the DARPA Grand Challenges, today’s leading manufacturers, and how self-driving cars work.