Ask Mr Brain...all will be explained
Why is the Mona Lisa painting so famous? Leonardo da Vinci's painting of a young woman - the Mona Lisa - is probably the most famous painting in the world. He painted it in Italy some time between 1503 and 1506.
Da Vinci did not actually finish many paintings, but the Mona Lisa was one of the 30 or so he did finish.
The painting is not very big - it is only 78 centimetres by 53 centimetres - but it changed the way people were painted. Most paintings of people before the Mona Lisa were very stiff and formal. The people were either heroes, goddesses or kings, and often they were painted in profile - from the side.
Mona Lisa was an ordinary person, and she is looking right at you in the painting, which was a breakthrough. In addition, there is her famous smile. Some people think it is an odd smile, but there is something about it that captures attention and makes people wonder what lies behind it. Da Vinci reportedly hired musicians and clowns to entertain Mona Lisa while he painted her because he was determined to do something different. People rarely smiled in earlier paintings.
Why is our middle finger longer than the other fingers? It probably has to do with evolution - with how our body works and how it evolved the way it did.
Some scientists think the different lengths of our fingers has to do with the 'geometry of closing'.
If you bring your fingers together into a fist, they all touch at the same time when they reach your palm. They meet equally, so when they grasp, they share the hand's work equally. Over millions of years of evolution, hands became this way because the shape works so well.
But anthropologists have pointed out that in some primates, the fourth finger is longest.