A traditional Nativity scene, Catalan-style
Outside Barcelona Town Hall, the Christmas crib takes pride of place on the cobblestones.
Mary, Joseph and the shepherds are all gathered around the baby Jesus in his manger, as loudspeakers emit the occasional animal sound for extra, rustic effect.
But this is Catalonia, and no crib is complete without one additional figure.
He is known in Catalan as the caganer. That translates most politely as 'the defecator' - and there he is, squatting under a tree with his trousers down.
At the nearby Christmas market amid the sprigs of holly and Santa hats rows of miniature, crouching country boys are lined up for sale.
Innocuous-looking from the front, their buttocks are bare and each one has a small, brown deposit beneath.
"It's typical of Catalonia. Each house buys one for Christmas," explains Natxo with a smile and a shrug as he shops. "I don't know why (we do it), it's just a tradition."
In fact, the caganer has been a feature of the Catalan nativity scene for at least two centuries.
"There was the legend that if a countryside man did not put a caganer in the nativity scene, he would have a very bad year collecting vegetables," explains Joan Lliteras, a caganer connoisseur.
He says the figurine is a symbol of fertility and good fortune.
Founder of an association dedicated to the squatting statues, the Amics del Caganer, Joan has a personal collection of 600 in his home.
But even this fan describes a clear, caganer etiquette.
"The caganer is never in the front of the nativity scene. That would be a lack of respect. He's always hidden in a corner, under a bridge or behind a tree and every morning the children play a game, hunting for the caganer," he explains.
A market trader selling (fully-clothed) singing bears tries some other theories: that defecation is the great leveller, a reminder that we are all equal.
Otherwise, he suggests, the focus on faeces is just another sign of how the Catalans love to be different.
The most popular caganer is still the traditional peasant figure in his floppy red Catalan cap.
But the classic kind has spawned a celebrity spin-off in recent years. Today's Christmas markets are full of famous people cast in clay, with their pants down.
The main workshop is north of Barcelona, outside Girona. A family business, caganer.com began by casting models of Catalan politicians.
The range now includes footballers and foreign presidents, rock stars and even royalty.
Complete with crown and golden slippers, Britain's Queen Elizabeth II is a firm favourite - depicted in the least regal pose possible.
Prince Charles was newly cast this year - though sales are slow - and there is already talk of Prince William and Kate Middleton joining the ranks, to mark their royal wedding.
But caganer-makers insist that being chosen as a model is quite the opposite of an insult.
"I don't know about the Queen but lots of politicians and footballers from Barcelona have come up and thanked me for their caganer," Sergi Alos claims, surrounded by piles of boxes marked 'Federer', 'Nadal', 'Bush' and 'Gordon Brawn' (sic).
"They say 'Thank you Sergi, it's an honour!' And that's how we like to present it, as a positive thing, an honour," he insists.
Among the international figures, President Nicolas Sarkozy, Silvio Berlusconi and the Pope are all strong sellers; Spiderman and Sponge Bob do well - complete with red and yellow "deposits" respectively.
And new-in this year - squatting alongside all the others - is Spain's champion team from the World Cup.
But in the shop downstairs there is a clear favourite with the foreigners.
"I'm buying four Obamas to send back home," American Tom Burns admits. He has been living in Catalonia for 15 years, and picks up a caganer Christmas gift each winter.
"People there just laugh and laugh. I have a sister who teaches at school and took one in one year. They were pretty incredulous at first, but now everyone wants one!" the shopper chuckles.
"I'm buying Obama," another shopper from San Francisco confirms. "With all due respect Obama, we love you dearly," says Nancy Duneuve.
Santa Claus alternative
But isn't placing a caganer in the crib hugely disrespectful - however far from the manger he squats?
Not according to Nancy.
"Not at all. It was the only thing the little shepherd boy had to give the Baby Jesus. So it's not at all disrespectful, it's a great gift."
Joan Lliteras argues the caganer should be protected and promoted as a uniquely Catalan Christmas phenomenon - an alternative to Santa Claus and other imports.
But it is not the only excrement-related festive tradition here. The markets are piled high with Caga Tios, too - the original Christmas log - which defecates each year for children. I'll spare the details.
So why are the Catalans quite so scatological, come Christmas?
"I am not able to answer this question," muses Mr Lliteras, seemingly puzzled.
"But it's something peculiar to here and we are proud of it. It's not a problem."