Technology Medium 15 points
Mystery
Pick your answer — then see the explanation and its source.
About Mystery of the Day
Each day brings one question about the world — space, nature, history, science, the human body and more. Choose an answer and the explanation appears, together with the source it comes from, so you can read further and check it for yourself.
Frequently Asked Questions
When does a new mystery appear?
Every day at midnight UTC. The page shows that moment in your own time.
Where do the answers come from?
Every mystery cites the source its answer comes from — such as a space agency, a museum or an official body — and links to it, so you can check it yourself.
How do points and streaks work?
A correct first answer earns 10 points for an easy mystery, 15 for a medium one and 20 for a hard one; a wrong answer earns none, and answering again does not count. Answering the daily mystery on consecutive days builds your streak. Your progress is kept only in this browser — there is no account and nothing to sign up for.