Ancient Civilizations
This city, buried by the eruption of Mount Vesuvius in A.D. 79, has provided archaeologists with an unprecedented look at daily Roman life.
Pompeii
This radioactive element, discovered by Marie and Pierre Curie, glows faintly in the dark and has atomic number 88.
Radium
This mass extinction event, caused in part by an asteroid impact about 66 million years ago, wiped out roughly 75% of Earth's species, including all non-avian dinosaurs.
Cretaceous Paleogene (K-Pg) Extinction Event
This ruler united Upper and Lower Egypt and is traditionally credited with founding Egypt's First Dynasty around 3100 B.C.
Narmer (also called Menes)
The pH scale is logarithmic, meaning a solution with a pH of 3 is this many times more acidic than a solution with a pH of 6.
1,000 times
This dinosaur's name means "swift seizer," and despite Jurassic Park, fossils suggest it was about the size of a turkey.
Velociraptor
The Rosetta Stone became famous because it allowed scholars to decipher this ancient writing system.
Egyptian hieroglyphics
This principle states that a system at equilibrium will shift to counteract a change in concentration, pressure, or temperature.
Le Châtelier's Principle
This feathered dinosaur from China provided some of the strongest fossil evidence linking dinosaurs to modern birds.
Microraptor
This wonder of the ancient world was built in Alexandria to guide ships safely into one of the Mediterranean's busiest harbors.
The Lighthouse of Alexandria (Pharos)
This scientist's periodic table famously predicted the existence and properties of several undiscovered elements.
Dmitri Mendeleev
This prehistoric marine predator, whose name means "big tooth," lived millions of years after the dinosaurs went extinct.
Megalodon
This Mesopotamian king is remembered for one of the oldest surviving written law codes in history.
Hammurabi
This element, with atomic number 74, has the highest melting point of any pure metal.
Tungsten
This flying reptile is often mistaken for a dinosaur, even though it belonged to a separate group called pterosaurs.
Pterodactyl (or Pteranodon)