Only about 2% of the world population has green eyes.
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Mars had an oxygen-rich atmosphere around 4 billion years ago
13
Cows can sleep standing up, but they can only dream lying down.
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The Lion's Mane Jellyfish is the largest jellyfish in the world. They have been swimming in arctic waters since before the dinosaurs (over 650 million years ago).
12
It's possible to die from a broken heart; it's called Stress Cardiomyopathy.
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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
Lurch, a Watusi bull, had the largest horns in the world.
32
In 2011, archaeologists discovered the skeletal remains of a Roman couple who have been holding hands for 1,500 years.
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