At first glance it doesn't have the "wow factor" that other paintings in the Louvre have.

It lacks drama.

But if we can ignore the hundreds of people that surround her.

If we can turn down the volume and just push the "off button" for a second.

What we actually see, is a quiet, contemplative portrait.

A portrait that is the greatest psychological portrait ever painted.

A portrait so ahead of its time, that centuries later, we are still trying to figure it out.

In 1517, the French king, King Francis I, offered Leonardo a job,

court painter - and engineer - and architect - to the King.

Leonardo, now in his sixties, moved to the Château of Amboise in France, and never went back to Italy.

He brought with him dozens of sketch books like these.

But just one painting... the Mona Lisa.

Leonardo knew how important it was. he knew it was a masterpiece.

Mona Lisa, is the end product of the greatest inquisitive mind in history.

A self-made man with a voracious appetite for knowledge.

A man who dedicated himself to the study of anatomy, geology and philosophy.

For Mona Lisa he used a thin grained piece of poplar tree

and applied an undercoat of lead white.

Leonardo painted with glazes that had a very small amount of pigment mixed with the oil.

So, how dark you want your glaze to be, depends on how much pigment you use.

He used more like a 'wash', which he applied thin, layer by layer.

Here you can see, two colours of contrast: Light and Dark.

When you apply glaze over both of them, you can see it starts to unify the contrast,

but also brings depth and luminosity.

The lead white undercoat reflects the light back through his glazes,

giving the picture more depth, and in essence, "Lighting" Mona Lisa from within.

As we move around the painting, that light shifts around.

He used tiny, almost invisible brushstrokes,

applied super slowly over months. Or in Mona Lisa's case, years.

By contrast, on her skin, brush strokes were applied in an irregular way.

And that makes the grain of the skin look more life-like.

All of these techniques pioneered by Leonardo, bring the painting to life.

Actually, let's start with what she's NOT wearing.

When was the last time you employed a professional photographer?

The answer is usually a wedding or a prom.

What were you wearing in your prom photo?

Your best clothes? Your best jewellery? Of course.

Being painted by one of the most celebrated and in demand painters of the day,

is your chance to really 'show off'.

And yet Mona Lisa is stripped of all the usual high status symbols.

Her clothes are nothing special, they tell us nothing.

Instead of the usual flamboyant, expensive outfits we usually see

in commissioned portraits of the aristocracy, hers are pretty simple for a wealthy woman.

Along with the complete lack of jewellery and the simple hair

they serve one purpose and one purpose only.

Leonardo made sure, we would not be distracted from the face of Mona Lisa.

Leonardo, uses the classic pyramid shaped composition that was introduced during the Renaissance.

It is an important change from the paintings of the 15th century.

The structure provides stability, but more importantly it provides a clear centre of focus,

and directs your gaze. In Mona Lisa's case it is pulling us into her face.

The Mona Lisa, is the earliest Italian portrait to focus on the sitter

in a three quarter length pose, rather than full-length. Why?

Because he completely fills the frame with his subject.

Making the painting more intimate AND cutting down on distractions.

This three quarter length pose becomes the norm for four hundred years after Leonardo pioneers it.

Today, we look at Mona Lisa's pose and it seems fairly normal.

But for its day, it was groundbreaking.

Previously subjects were stiff and upright. Aristocratic.

But Mona Lisa is relaxed, her hands are resting gently on the arm of her chair

As she turns towards us

Almost... as if its a snapshot.

Mona Lisa is also rather content and self-assured,

which is more how aristocratic men were portrayed, not women.

We are looking directly into her eyes and she is looking directly at us.

Women in paintings just didn't do that.

They didn't look boldly and directly at the viewer.

The entire painting deviated from the traditional way

women were painted in Italy.

Portraits were usually done with an open sky as the background,

a monotone background, or a simple room.

Mona Lisa is in front of a complicated landscape

that only existed in Leonardo's imagination.

Paintings of this period had both the subject and the background

in sharp focus. Whereas the background of Mona Lisa

seems to fade or become more blurred and out of focus, the further

from the subject it extends. This is aerial perspective.

And Leonardo invented it.

Behind Mona Lisa, the vast landscape recedes to distant icy mountains.

A path and a bridge are our only indication of human presence.

The curves of her hair and clothing, reflect the rolling valleys and rivers behind her,

connecting humanity and nature.

A favourite theme of Leonardo's.

The earth seems to twist like her torso.

Look at the river on the right.

It flows into the scarf over her left shoulder.

We see that she is connected with the earth.

There is another visual trick that gives the illusion of movement.

The horizon of the landscape does not quite line up behind the figure.

It is very slightly skewed. Whilst her shoulders are painted level

Leonardo knew that our brains would struggle with this conflicting visual information.

We know that the horizon should line up so we read it as level.

This then cause us to interpret the shoulders as being on a slant. Which they are not.

As our brain corrects this, it creates an illusion of movement,

as if the figure 'shuffles' a little bit in its frame.

The effect only works with paintings. Not sculptures or real-life,

since the elements of perspective and light and shadow are fixed in a painting,

and don't change.

They look the same, no mater from what angle you look at it.

It's a real phenomena, but not unique to this painting.

The first technique he invented was "sfumato" meaning "smoky".

Sfumato is a blending technique for softening the transition between colours

to make sure there are no sharp unnatural lines.

Through layers and layers of those thin, semi-transparent glazes,

he blended everything sfumato style.

His brush strokes so subtle as to be invisible to the naked eye.

In essence, the sfumato technique takes painting one stage further.

It allows us to look at a painting the way our eyes work tonally.

It allows 'depth of field', never seen in a painting before Mona Lisa.

We can see what a master of sfumato he was, when we look at the shading around Mona Lisa's eyes.

The other technique he invented is "Chiaroscuro" from the Italian for "light/dark"

Where he contrasts prominent shade of light and dark to create the illusion of 3-dimensional forms.

Seeing Mona Lisa for the first time five hundred years ago, must have been astonishing.

Then there is the smile that brings everything together.

Before, during, and long after the renaissance, artists did not paint their subjects smiling.

When you think about it, portraits are generally very serious.

It's easy enough to smile for a few minutes, but not for the weeks, if not months it takes to paint a portrait.

Leonardo kept her happy though, by employing musicians and jesters.

Look at her for a while.

Really look into her eyes.

First she is smiling and then she is not.

The smile comes and go's as we scan the face.

But when we look away, the smile lingers.

When Leonardo was perfecting Mona Lisa's smile

he was spending his nights in the morgues, peeling the flesh off cadavers, exposing the muscles and nerves underneath.

He became fascinated by how a smile works, and analysed every possible movement

of each part of the face. Working out the origins of every nerve

that controls every facial muscle.

We can see this research in his anatomical drawings.

Here we see puckered lips, pouting lips, the muscles that move the mouth.

Then almost forgotten... at the top of this page, is a simple drawing of a gentle smile,

sketched lightly in black chalk. Even though the fine lines at the end of the mouth turn down slightly,

The feeling is, that the lips are smiling.

This simple anatomical drawing, is the beginning of Mona Lisa's smile.

Astonishingly, Leonardo already knew from his optic studies

that light rays do not come to a single point in the eye, but instead, hit the whole area of the retina.

And this is the key to her enigmatic smile.

In the year 2000, Dr. Margaret Livingstone, a Harvard neuroscientist,

discovered that Mona Lisa's smile comes and go's because of how the human visual system is designed,

not because the expression is ambiguous.

She explained that the human eye has two distinct regions for seeing the world.

A central area called the "Fovea" is where people see colours, read fine-print, and pick out details.

And the "peripheral" area surrounding the Fovea is where people see black and white, motion and shadows.

When we look at a face, we spend most of the time focused on the other person's eyes.

So when a person's centre of gaze is on Mona Lisa's eyes.

The less accurate peripheral vision is on her mouth.

And because peripheral vision is not interested in specific details,

it also picks up shadows from Mona Lisa's cheekbones.

This is where both his sfumato and chiaroscuro techniques, come into their own.

As we look into her eyes, the shadows and tones suggest the curvature of a smile.

But when your eyes go directly to Mona Lisa's mouth, your central vision doesn't see the shadows.

And she isn't smiling. Smirking at best.

We can prove this theory, quite simply, by staring directly into her eyes,

and think about how much she is smiling.

Then scan back and forth between her eyes and her lips, and her expression changes.

That is NOT your imagination. It is all to do with how we SEE - not how we THINK.

The genius of Leonardo is that he understood this five hundred years ago!

The Mona Lisa became the most famous painting in the world. Not just because of hype or chance.

But because for five hundred years, viewers have been able to feel an emotional engagement with her.

Before the Mona Lisa, portraits lacked mystery. Artists only represented outward appearances.

Mona Lisa however is "alive'. A living, breathing woman.

With a soul.

When you stand in front of the Mona Lisa, you are looking at more than just a portrait of an individual.

You are looking at the accumulated knowledge of a genius.

Who blended art, science and "magic" to create a profound meditation

on what it means to be human.

Whether she is "Mona Lisa", "La Gioconda", or "La Joconde",

she is the face of a revolution in art.