The process of the decay of unstable nuclei is called radioactivity.
The Incas´ rudimentary weapons were inadequate in their struggle against the Spanish Conquistadors.
The ‘upright man’ used tools and could set fire.
The river and marine sailing boats of ancient Egypt were one-masted, oared boats
The submarine designed by the Spanish inventor Narcís Monturiol was a pioneering work in the history of underwater navigation.
Concave and convex lenses are used for the correction of short-sightedness and far-sightedness.
English sailing ships were among the best ships in the 17th-19th centuries.
Spanish conquerors owed their success to their armour and firearms.
Public schools in villages played an important role in education.
The Ottoman army included janissaries (paid warriors) and sipahis (vassal knights).
Dicotyledons have two embryonic leaves (cotyledons), while monototyledons have only one.
The building complex was one of the most important Benedictine abbeys for centuries.
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.
The French monarch got his epithet because of his opulent and extravagant lifestyle.
Keeps were typical buildings in the Middle Ages, also built independently from castles.
One of the greatest archaeological finds of the 20th century was the tomb of the Egyptian pharaoh.
Edges, diagonals and faces of a cube can be identified by its vertices.
The animation offers a summary of the history of aviation from the Middle Ages.
The Greek fleet owed their success to their good tactics and their fast and easily manoeuvrable ships.