A lump of pure gold the size of a matchbox can be flattened into a sheet the size of a tennis court.
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Only about 2% of the world population has green eyes.
36
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
The oldest stone tools found are dated from 2.7 - 2.9 million years ago. The species that made these tools is unknown.
13
In 2011, archaeologists discovered the skeletal remains of a Roman couple who have been holding hands for 1,500 years.
81