Pollution is the detrimental effect of human activity on the natural environment.
Viruses consist of protein and DNA or RNA; they reprogram infected cells to produce more viruses.
The church of the "Holy Wisdom," built in the Byzantine Empire, had been one of the largest religious buildings until 1935, when it was converted into a museum.
The round tower of the largest fort in the Arabian Peninsula had an ingenious defense system.
Large carnivores, perhaps the best known of dinosaurs.
This animation demonstrates different types of volcanic eruptions.
This animation demonstrates the type of engine most commonly used in cars.
The most famous and most magnificent amphitheater of Rome was built in the 1st century.
The ear converts the vibrations of air into electric signals which are then processed by the brain.
This animation presents the formulas to calculate the perimeter and area of shapes as well as the surface area and volume of solids.
The desalination process produces drinking water from seawater.
This animation introduces the most important organ systems of the human body.
The world's most famous citadel, the Acropolis of Athens was built in the 5th century B.C., during the Age of Pericles.
This animation demonstrates how the Earth and the Moon were formed.
This animation presents some interesting facts in physical geography.
Visit the workshop of the Renaissance polymath and his most influential inventions and works of art.
The main sources of water pollution are industry, agriculture and urban areas.
A metropolis is a large city with a population of over 1 million people.
The International Space Station is a habitable satellite built with the cooperation of 16 countries.
The eye is one of our most important sense organs. When stimulated by light, electric impulses are produced by its receptors.