Satellites orbiting the Earth can be used for civilian or military purposes.
Archimedes was one of the most brilliant Greek scholars of ancient times, who made his mark with military inventions as well.
Long-necked herbivorous dinosaur with a robust body.
A compound formed as white smoke during the combustion of phosphorus.
The ancient city located near the river Euphrates was an important Sumerian center.
Edges, diagonals and faces of a cube can be identified by its vertices.
One of the most important religious military orders, formed in the era of the Crusades.
The Möbius strip and the Klein bottle are special two-dimensional surfaces with only one side.
The fearsome looking Aztec warriors could not stop the Spanish conquistadors with their primitive weapons.
The outcome of one of the greatest battles in the history of the ancient East (fought by the Egyptians and Hittites) was indecisive.
This animation presents some interesting facts in physical geography.
Inhabitants of the northern part of the Netherlands have successfully fought the sea since the Middle Ages.
One of the oxoacids of nitrogen. Colorless, moderate acid with a pungent odor, that exists only in aqueous solution.
Tidal power stations utilize the daily fluctuation of the water level for producing electricity.
The Greek fleet owed their success to their good tactics and their fast and easily maneuverable ships.
As opposed to underground mines, in open-pit mines the layers covering coal are removed, coal is extracted on the surface.
Treated sewage water can be used in agriculture and industry.
The Earth is divided into 24 time zones. Standard time is the time used within time zones.
More than one million people died in the WWII Nazi death camp located in present-day Poland.
This animation demonstrates the five regular three-dimensional (or Platonic) solids, the best known of which is the cube.