Sometimes, just one letter makes all the difference. In this quiz, you’ll be given a complete word that can have another meaning if one letter is added. Your job is to figure out which single letter ...

Try your hand at these tricky visual puzzles and give your brain a boost!

Each week, New York Times crossword puzzle editor and NPR's Puzzlemaster Will Shortz presents an on-air quiz to one contestant and gives a challenge for listeners at home.

While puzzles are often seen as solitary activities, International Puzzle Day shines a light on their powerful social side.