Rubicon is trivia you type, with no multiple choice. There's nothing to pick from. You write what you know, and an AI judge marks what you meant, typos and all.
GeoGuessr drops you somewhere on Earth and doesn't give you a list of countries. You look around and work it out. Rubicon does the same thing with questions about everything else. There are no four options to rule out and nothing to recognise, so the answer has to come from you.
Think of it as GeoGuessr for the brain. You can play it alone, one on one with a friend, or with a whole room at once.
Nothing gets spoiled. Four options tell you what kind of thing the answer is before you've even thought about the question. An empty box tells you nothing.
You're marked on whether it's true. "The bloke who did the printing press" scores the same as "Johannes Gutenberg". Spelling and phrasing don't count against you. Being wrong does.
Luck is out. With four options, some of your score is always lucky guesses. Here your score is what you actually know, and Rubicon builds you a map of it across every subject.
Everyone plays in their own language, and there are 53 to choose from. A room gets the same question at the same moment, each player in their own language, and everyone is scored in the language they wrote in.
You also play as someone. Pick one of 104 characters from history, like Hypatia, Ada Lovelace or Mansa Musa. Each one is strongest in the subjects they were known for.
Play alone at your own pace, duel another player or an AI, or join a room where everyone answers the same questions together. There's also the Daily, a new set of questions every day that's the same for everyone. The core game is free and runs in your browser, so there's nothing to install.
More: what Rubicon is, questions and answers, every character, pricing.