To an outsider's eyes, there are all the trappings of a colourful religious festival - shops brimming with festive goods, people stocking up on fancy foods and sweets, and houses adorned with bright flowers and decorations.

But while most religious occasions are all about devotion to God and life, this one in Mexico is all about death.

It is called the Day of the Dead, and stretches from 1 November all night and into the following day.

An Indian woman watches over the candle-lit grave of a relative in Tzintzuntzan

Although it closely mirrors the Catholic Church's widely-celebrated All Saints Day and Halloween, this is a uniquely Mexican event.

Instead of the sombre, emotional day in other parts of the world when families visit the graves of their relatives, the Mexicans have turned it into a huge fiesta - a joyous family reunion with their ancestors.

"One of the fundamental contradictions in Mexico is that we celebrate our dead with a fiesta, with music, with colour, with food," says historian and social commentator Guadelupe Rivera Marin.

Cycle of life

"This is a contradiction that we must hold on to, because it is something that has given us personality as a people, as a country, as a nation."

Sugar skulls decorate an offering to a dead relative in Mexico City

According to anthropologists like Professor Eduardo Matos, the Day of the Dead it is a hybrid of Catholic and ancient Aztec Indian beliefs, rooted in the Aztec ideas on the cycle of life.

"They observed that throughout the year there was a rainy season when the landscape turns green and plants grow. That's followed by a dry season that brought death. It was a constant life and death cycle which they observed in nature and applied to themselves," he says.

In the Aztec tradition, two months were set aside to commune with the dead - one month for children and another for adults. In those months, the Indians would set up altars to individuals, and adorn them with the spirit's favourite real-world food and drinks.

Edible skulls

Now, despite the fact that the Catholic Church has done its best to turn the Day of the Dead into a solemn affair, the festival is still rooted in the ancient beliefs.

Day of the Dead markets sell chocolate skulls

Its central symbol is the skeleton in all its ghoulish forms. There are chocolate and marzipan skulls, with mint teeth and sweets for eyes.

There are skeletons dancing on sticks, paper doilies depicting skeletons, skeletons made out of paper-mache. And most disconcertingly, model skeletons in tiny scenes of every day life.

"We try to show that the spirit world is just like ours," says Jose Luis Angeli, who has brought his family to the cemetery in the town of Tzintzuntzan, in the central state of Michoacan.

"No one likes the idea of dying, but we believe that our ancestors are still very much alive."

All night party

Like tens of thousands of families across Mexico, the Angelis have decorated the graves of their relatives with bright orange marigolds, dozens of candles and a huge feast.

They have brought music along to complete the all-night fiesta that was all about remembering the good times.

"I think these memories are important," Jose Luis says. "This night is the time when we remember with great joy the people who lived with us and left us so much.

"Reliving the good times is what it's all about - the bad ones are the ones that hurt, so we try to avoid them."

And although the Church is still struggling to come to terms with the festival's pagan origins, priests like Father Jose Juan Sainz Luna believe it is even more important to Mexicans than days like Christmas and Easter.

"In Mexico's case, I think that the birth and death of a real person is more important than Christmas. This may scare the traditional Catholic thought," he says.