Regular square pyramid

A regular square pyramid is a right pyramid with a square base and four triangular faces.


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

Underground waters

Groundwater and aquifers are types of underground waters.


These special dolmens located in present-day Netherlands were built about 5,000 years ago.

Hussite wagon fort

The Hussites mastered the use of war wagons in the 15th century.

Pula Arena (Pula, 1st century)

The Pula Arena, located in present-day Croatia, was one of the largest Roman amphitheatres in the Antiquity.


Waterfalls form where a river flows over a steep precipice in its course.

Hot air balloon

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

The Varaždin Castle (16th century)

This stunning castle is situated in northern Croatia.

Water turbine, generator

Water turbines convert the kinetic energy of water into electric current.

Location of origin of livestock and crops

Domesticated animals and crops originate from various parts of the world.

Megalithic cultures in Europe

Structures consisting of enormous stone blocks, dating back thousands of years, are monuments of megalithic cultures.

Soil pollution

This animation demonstrates the main sources of soil pollution.

Monsoon wind system

In summer, monsoon winds bring heavy rainfall from the ocean to the continent.

Volume of a tetrahedron

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

The secondary structure of proteins

Polypeptide chains are composed of amino acids and can appear in alpha-helix or beta-sheet form.

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.

Oxygen cycle

The oxygen cycle describes the movement of oxygen within its three main reservoirs.

The phosphorus cycle

The phosphorus cycle describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

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