The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21
Your thumb is about the same size as your nose.
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No one knows Albert Einstein's last words. Just before he passed, he spoke several words in German, but his nurse only knew English.
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Scientists at the Zhejiang University in China have developed an ultra-light material known as carbon aerogel.
3
In Georgia, there is an airtight room called the Crypt of Civilization that was sealed in 1940. It contains numerous artefacts documenting what life was like at the time of sealing, and is scheduled to be opened in the year 8113 to show people of the future exactly what life was like.
13
The oldest glowing lightbulb was first switched on in 1901 and lives in fire stations in Livermore, CA. It is known as the Centennial Light.
118
Only about 2% of the world population has green eyes.
36