A species of mollusc widespread in freshwaters.
An extinct group of Cephalopoda, with solid external skeletons. They are excellent index fossils.
Limestone is a widely and diversely used material.
This animation demonstrates the anatomy of birds through the example of mallards.
Crystalline allotrope of elemental carbon, the hardest known natural substance.
Maharajas were Hindu rulers of large regions of India.
A sailing vessel with characteristic lugsails used for both military and trade purposes.
The French monarch got his epithet because of his opulent and extravagant lifestyle.
The best-known piece of the Hungarian Crown Jewels is the Holy Crown.
The largest type of Arab sailboat, most commonly used as trading vessels in the Persian Gulf.