Cows can sleep standing up, but they can only dream lying down.
745
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
No one knows Albert Einstein's last words. Just before he passed, he spoke several words in German, but his nurse only knew English.
154
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
There is a persistent storm in Venezuela that produces lightning 140 to 160 nights a year, 10 hours per day and up to 280 times per hour and has been going since at least the 16th century.
25