It is estimated that there are over 3 million undiscovered shipwrecks in the world's oceans.

Penguins have a specialised gland above their eyes that filters salt from their blood. This allows them to drink seawater, excreting the salt through their beaks or nostrils.

The reason British pubs have unique (and sometimes strange) names dates back to medieval times, when pictorial signs with animals or objects helped the illiterate masses to identify them.

Farm-raised salmon is actually grey, due to having a different diet to wild salmon. Fish farmers dye salmon red to make them look more natural.

Members of Southeast Asia's Bajau tribe can hold their breath underwater for up to 13 minutes. Their sea-faring lifestyle has led to the evolution of spleens up to 50% larger than average, enhancing their bodies' oxygenation.

At one point in Earth's history, it rained for over a million years straight, caused by intense volcanic activity and atmospheric changes.

The phrase 'running amok' originates from the Malay word 'mengamok,' meaning to make a furious and desperate charge. Captain Cook used it to describe the behaviour of Malay tribesmen.