A group of researchers from Lausanne (Switzerland) found that there are genes that determine the quality of sleep. It was thus proven that insomnia, as well as good sleep, can be hereditary.
The first city in the World that has reached one million inhabitants was Rome, around 133 BC. London got its one million inhabitants in 1810, and New York in 1875. Today, there are over 300 cities with more than a million inhabitants.
Baby gorillas are breastfed for four years.
A four-year-old child will, on average, ask about 437 questions a day.
Oysters can change their sex from male to female. They can do this countless times.
In the year 1900, the number of human population was 1.5 million, of whom a quarter lived in Europe.
