Why do we respond when we hear a scream?

6 places where you can (safely) watch lava flow

6 surprising facts about ladybugs

Revel in this 'magic cloud' of synchronized starlings

Mysterious 'Silkhenge spider' is a master architect

Killer whales vs. shark: Drone footage shows rare attack

David Attenborough concludes 'Planet Earth II' with heartfelt appeal

Bizarre 'snowball cloud' forms over Japan

World's highest plants discovered 20,000 feet above sea level

Africa's tallest tree discovered towering on continent's highest mountain

Photographer snaps rare shot of 'ghost rainbow'

Ant colonies discovered farming their own fruit crops