Air pollution

This animation demonstrates the main sources of air pollution: agriculture, industry and urban settlements.


Airports provide infrastructure and services necessary for aviation.


Ports must provide necessary infrastructure and services for industry and marine transport.

Southern wood ant

An ant colony consist of a queen, male ants and workers.

Desktop computer

This animation demonstrates the structure and most important peripherals of desktop computers.

Optical instruments

A wide variety of optical instruments are in use today, ranging from microscopes to telescopes.

Battle of Issus (333 BC)

The battle ended with the overwhelming victory of the Macedonian army over the Persian army led by Darius III.

Medieval Chinese Emperor

The Emperor of the vast Far-Eastern empire was the lord of life and death.

Comparison of real fruits and pseudofruits

The pericarp of real fruits develops from the carpel, while the pericarp of pseudofruits develops from other parts of flowers.

Freshwater pearl mussel

A species of mollusc widespread in freshwaters.

European mole

Moles are small subterranean mammals with modified, spade-like forelegs.

Dividing Space into Regions by 3 Planes

Division of space by three intersecting planes in several different arrangements.

Attack of Pearl Harbor (1941)

The United States entered World War II after the devastating attack by the Japanese navy.

Volume of a tetrahedron

To calculate the volume of a tetrahedron we start by calculating the volume of a prism.

Types of synovial joints

Synovial joints can be categorised by the direction of movement they allow.

Hot air balloon

A hot air balloon is a balloon aircraft which is lifted by hot air.


Regular dice can be used for solving statistical and probability exercises.

Native American settlement (Crow Nation)

The Crow are Native Americans who inhabited the Yellowstone River valley.

El Niño

A periodic climate pattern that occurs across the tropical Pacific Ocean every five years.

Warm front, cold front

Cold and warm fronts are formed where bodies of cold and warm air meet.

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