Surface tension is the property of a liquid that allows it to obtain the smallest surface area possible.
The Hussites mastered the use of war wagons in the 15th century.
These special dolmens located in present-day Netherlands were built about 5,000 years ago.
Many of the most important food crops we consume belong to the family of nightshades.
The animation presents the largest mountains, plains, rivers, lakes and deserts of the Earth.
Paper was invented more than two thousand years ago.
Modern Slavs live in 14 European countries that can be classified into 3 groups.
The building material of the cell walls and fibres of plants.
Eurypterids are an extinct group of Palaeozoic aquatic arthropods.
A white, water-soluble, sweet compound known as sugar.
Oil tankers appeared in the late 19th century; today they are among the largest ships.
Cosmopolitan monocots inhabiting watersides.
Formic acid is the simplest carboxylic acid.
The Kepler space telescope was launched by NASA to discover Earth-like planets orbiting other stars
Ziggurats were typical terraced step pyramids used as temples in ancient Mesopotamia.
Karst formations include dolines and dripstones.
These excellent shipbuilders and sailors travelled great distances on the seas and rivers.
A sailing vessel with characteristic lugsails used for both military and trade purposes.
Farming techniques evolved with the development of human civilisation in the Middle Ages and the Modern Age.
Tardigrades can survive in extreme environments, they can even stay alive in outer space.