A zither is one of the typical instruments of Hungarian folk music, played by strumming or plucking the strings.
Caliphs, considered successors of the Prophet Muhammad, were the most important religious leaders of Islam.
Ancient Persian monarchs were famous for the size of their empire and their wealth.
American soldiers fought in almost all major theatres of World War II.
Subterranean rodents widespread in Central- and Eastern Europe.
Colour a map with the fewest number of colours possible, so that no two adjacent regions have the same colour.
Automobiles have evolved a lot since the late 19th century.
This animation demonstrates the development of freight transport, from horse-drawn carts to modern lorries.
A game about sights around the world.
The Arch of Triumph was built at the entrance of the Forum Romanum, to commemorate Emperor Titus’ victory in the Siege of Jerusalem.
During World War I, Britain was part of the military alliance called the ´Triple Entente´.
This animation demonstrates the most important seas and bays.
Soldiers of the Wehrmacht in World War II were well-trained and well-equipped with modern weapons.
Small farms usually located near the border of rural towns, inhabited by peasants.
An exercise about the generation of solids of revolution.
The theorem formulated by Leonhard Euler describes one of the basic properties of convex polyhedra.
This animation demonstrates various types of cones and pyramids.
This animation demonstrates the angle of inclination of lines and planes in various positions.
Drums are played by hitting the membrane. There are many versions of drums.
The structure of fortresses developed together with military technology.