When the Sun, Earth, and the Moon are arranged in a straight line, the Moon can partially or completely obscure the Sun.
Typical settlements of the Norsemen were not only established in Scandinavia, they appeared on distant areas as well.
The magnificent capital of the Aztec Empire astonished even the Spanish Conquistadors.
Certain mushrooms are poisonous and can be fatal for humans when consumed, while others are edible and used widely in cooking.
The ancient Roman arena became well-known for the chariot races held here.
Mercenaries of the ancient Roman army were well-trained and well equipped with the most up-to-date weapons.
In the Tudor Era around 200 buildings were built on the bridge across the River Thames.
The Parisian prison became legendary after the Revolution of 1789.
Cannons also appeared in naval warfare.
Skeletal muscles form the active part of the locomotor system: they move the bones they are attached to.
Today only one of the Wonders of the Ancient World is still intact: the Pyramids of Giza.
The seminomadic lifestyle of the Bedouin adapted to the climatic and environmental conditions of the desert.
The excellent road and aqueduct system covering the whole empire reflects well the development of the Roman civilisation.
A series of fortifications built to prevent incursions from northern nomadic groups.
The step pyramid, built in the 27th century BC, was the first pyramid in Egypt.
The large intestine is the last section of our digestive track.
The army of Alexander the Great successfully deployed siege towers in its attacks against fortifications.
This animation demonstrates the structure and operation of electron microscopes.
Machines converting the energy of flowing or falling water into useful forms of power were already in use in the Middle Ages.
Nuclear fusion will serve as an environmentally friendly and practically unlimited source of energy.