The possibility that there might be many parallel worlds has just become a little more likely.

Politician Douglas Carswell has been arguing with scientists about what causes the tides. We've figured out who's right.

Some uncomfortable problems in our understanding of life.

This problem about an infinite sum has a surprising answer.

This surprising result about 3D shapes tells us something deep about the nature of space.

Euler may not have cracked this problem completely, but it led to a lot of important work, including on what we today know as sudoku.

Can you move a knight on a chessboard so that it visits every square exactly once? Euler was one of the first to analyse this problem systematically, but some questions about it are still open today.

Can you find a path through on this city map that crosses every bridge exactly once? Euler's answer to this problem started off the filed of graph theory.