Primal emotions like fear and disgust appear universally — but complex emotions vary significantly across cultures.

The Milgram obedience study examined responses to authority.

Facial expressions are recognized across many cultures.

Extreme sports athlete Travis Pastrana became the first person to land a double backflip on a motorcycle at X Games 2006.

Particles can exist in multiple states until observed.

The Large Hadron Collider is the world's largest particle accelerator.

In Aztec mythology, the sun and moon were created when two gods threw themselves into a fire at Teotihuacan.

Particles can exist in multiple states until observed.

The Roman festival of Saturnalia — involving gift-giving, feasting, and role reversals — influenced Christmas traditions.