A symbol of division and oppression, the Wall tore a city and numerous families apart.
Medieval townhouses were built from stone or brick and were several stories high.
The B-24 Liberator was an American heavy bomber aircraft, built in large numbers, that was used on every front during World War II.
A widespread snail species, also popular as food.
Life magazine picked Gutenberg's invention of mechanical movable type printing as the most important event of the second millennium.
The diameter of the Sun is about 109 times that of the Earth. Most of its mass consists of hydrogen.
A mushroom is the fleshy fruiting body of a fungus, made up from hyphae.
The Earth is composed of several spherical layers.
Due to the Earth´s tilted axis, the angle of the Sun's rays at given latitudes continuously changes during the year.
These Paleolithic statuettes probably symbolize fertility and prosperity.
The geographic coordinate system enables every location on the Earth to be exactly specified.
The difference between the temperature of the polar and equatorial zones causes atmospheric circulation which is affected by a number of factors, including...
This animation demonstrates the internal structure of the brain.
The eye is one of our most important sense organs. When stimulated by light, electric impulses are produced by its receptors.
The pancreas and the liver empty digestive juices into the duodenum.
Lymph vessels carry lymph to the blood vessels, while lymph nodes are integral parts of the immune system.
Eukaryotic cells contain a number of organelles.
This animation introduces the studies of astronomers and physicists whose works fundamentally changed our view of the universe.
Bacteria occur in a wide range of shapes, including spheres, rods and spirals.
The heart is the central pump of the cardiovascular system beating several billion times over our lifetime.