For thousands upon thousands of years, we didn't know whether the other stars in the Universe were even like our Sun, much less whether they had planets around them like we find in our Solar System. Over the past 25 years, however, that question has not only been answered, but we've discovered thousands of confirmed planets. Even more exciting, we've found that the star systems out there are similar to our own in some ways but tremendously different in others, and that there are already more than 20 rocky planets known that are at the right distance to have liquid water on their surface, given Earth-like atmospheres. This includes the closest star to our own: Proxima Centauri, whose planet 'Proxima b' just might be our first step into the Universe beyond our Solar System. Enjoy!