There is no simple answer to this question as there are a multitude of startups out there vying for the title of "best." Some might argue that the best startup is the one with the most innovative product or service, while others might say that the best startup is the one with the most potential for growth and scalability. Ultimately, it depends on what you personally value in a startup.
Some of the most well-known and successful startups in the world include companies like Airbnb, Uber, and Pinterest. These companies have all achieved massive success by disrupting traditional industries and revolutionizing the way people interact with technology. If you're looking for a startup that has the potential to change the world, then these are some good examples to look at.
Of course, there are many other startups out there that are doing amazing things and are worth considering as well. It really just depends on what you're looking for in a company. Do your research and find a startup that you think has the potential to be the best in the world.