Biogas power plant

Biogas can be produced from organic material (manure, plant waste, organic waste) using...

Turkish bath (16th century)

One of the positive influences of the Ottoman invasion of Europe was the construction of...

Jameh Mosque (Isfahan, 15th century)

Its architectural solutions and ornamentation rank this mosque among the masterpieces of...

Typical dwelling types

Every era and every culture has specific residential buildings.

Planaria gonocephala

One of the most common types of flatworms.

Southern plantation with slaves (USA, 19th century)

Before the American Civil war the use of slaves on plantations was typical in the...

Lead-acid battery

Electrochemical processes in a lead-acid battery produce electric current.


A mammal with features typical of reptiles: it lays eggs and has a cloaca.

How does it work? – Cinema projector

This animation demonstrates the design and operation of a traditional cinema projector.

Monsters of the Palaeozoic: sea scorpions

Eurypterids are an extinct group of Palaeozoic aquatic arthropods.


An extinct group of Cephalopoda, with solid external skeletons. They are excellent index...

Oil tanker

Oil tankers appeared in the late 19th century; today they are among the largest ships.

Reed and bulrush

Cosmopolitan monocots inhabiting watersides.


Modern Slavs live in 14 European countries that can be classified into 3 groups.


Tardigrades can survive in extreme environments, they can even stay alive in outer space.

Underground coal mining

As opposed to opencast mines, in underground mines the layers covering coal are not...

The first days in school

Learn the concept of colours, numbers, letters and shapes while playing


A transformer is a device used for converting the voltage of electric current.


A fjord is a long, narrow inlet with steep sides, created in a valley carved by glacial...

Scots pine

One of the most common tree of the pine family, native to Eurasia.

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