10 things we didn't know before the 21st week of 2007

1. Pizza was known as “Italian Welsh rarebit” in 1950s Britain.
2. Using a gas-fired patio heater for just one hour can waste enough energy to make 400 cups of tea, according to Friends of the Earth.
3. Laurence Olivier and Tintin's creator Herge were born on the same day.
4. A swarm of bees can ground a Boeing 737.
5. On the first day of filming Star Wars in the deserts of Tunisia, the country experienced its first major rainstorm in 50 years and a rest day had to be called.
6. Sharks have virgin births.
7. Articles of 50,000 words - parliamentary reports in particular - were common in the Times in the early 1890s, just as the first tabloid newspapers came into being.
8. Japanese whalers in the 17th Century buried the foetuses of the pregnant whales they caught in a special graveyard facing out to sea.
9. One in four house sales fall through.
10. Captive elephants often don’t know how to look after their young because they don’t work on instinct – in the wild, calves are looked after by the herd and this is how young females learn mothering skills.).

(Source: BBC)