By 2021 there will be over 1 billion surveillance cameras installed around the world.
Rock layers are dated by the period in which they formed.
Moss was the first plant on earth.
It takes more than 500 years to form 2 cm of topsoil.
Sir Isaac Newton invented the colour wheel.
There are 197 countries in the world.
Japan has 108 active volcanoes.
Pumpkins grow on vines and have seeds, which means they are a fruit, not a vegetable.
Taxonomy is the science of naming a new species.
The Danish language has no word for “please”.
The human skull consists of twenty-two bones.
The human eye can see seven million colours, while computers can display around 17 million.