Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
skin depth
Directory
References
Discover
Time zone map with standard time zones and International Date Line
Why Are Some Time Zones 30 Minutes Off Instead of an Hour?
Artist interpretation of space asteroids impacting earth and moon. Meteoroids, meteor impact, end of the world, danger, destruction, dinosaur extinct, Judgement Day, Doomsday Predictions, comet
Major Mass Extinctions
Close up of praying mantis walking on stone ground against a blurred background in Japan
6 Animals That Eat Their Mates
New York NY/ USA- November 23, 2018 Hordes of shoppers throng the Macy's Herald Square flagship store in New York looking for bargains on the day after Thanksgiving, Black Friday.
Why Is It Called Black Friday?
Nelson Mandela, undated photo.
15 Nelson Mandela Quotes
San Francisco, California/USA-1/18/20: Womens March at Civic Center marching with signs of political protest regarding equality also embracing 2020 presidential candidates and celebrating equality
How Does the U.S. Government Define the Difference Between a Protest and a Riot?
Estimated battle casualties, Normandy invasion, World War II. WWII, D-Day
Estimated Battle Casualties During the Normandy Invasion and Campaign to Liberate Paris (June–August 1944)

skin depth

physics