Riddles can be a great way to pass time on a boring road trip, or to test the waters of your pool of friends and see which of them is the smartest. Hard riddles can take the shape of anything from simple questions to paragraph-long logic problems that are best done with some graph paper and one of those giant pink erasers. Some of the impossible riddles collected here are sure to break your brain for at least a week, but once you solve them you’ll feel like the smartest person on the planet. FYI, if you want to try your hand at these questions most people can’t solve without any help, don’t read the spoilers and answers written below every riddle.

Some of the hardest riddles and brain teasers are incredibly simple questions that have been around for years. In the time that it’s taken to find the Higgs Boson, build affordable electric cars, and hack an iPhone, the world is still having trouble figuring out who had Einstein’s fish. If you’re someone who likes to relax with a nice mystery, these hard brain teasers are the perfect way to spend an afternoon (or longer). Your IQ might even go up a few points, who knows?! If you think you’re ready, start digging into these questions and riddles that most people can’t solve.