First, a confession. Although it's regarded by many Mexicans as their country's prettiest city, I'd never heard of Guanajuato until I set foot on a train on France's Cote d'Azur last northern summer.
In my carriage were a loquacious young couple; the man from the US, the woman from Mexico. She was drop-dead gorgeous. He was clearly smitten. "You know what," he said, gazing at her like a love-struck puppy. "She says she's the ugliest girl from her city. Can you believe this? Apparently, Guanajuato is famous for its beautiful chicas."
My interest piqued, and knowing that I would be heading to Mexico in a few months' time, I vowed to include it on my itinerary.
A four-hour bus ride north of Mexico City, Guanajuato far exceeded expectations - though not, perhaps, for the reasons that lured me there.
World Heritage-listed by UNESCO and the birthplace of Mexico's most famous painter, Diego Rivera, the city is wedged into a canyon, 2000m above sea level. This semi-arid area was known to the indigenous people as Quanax-huato ("mountainous place of frogs") and the Spanish Conquistadors initially had no interest in it.
All that changed, however, in the mid-16th century, when huge deposits of gold and, especially, silver were found amid the craggy landscape. Over the next three centuries, these riches transformed Guanajuato into the wealthiest city in Mexico, bankrolling many of its architectural jewels and filling the coffers of the Spanish Crown (plus the mine owners).
Today, Guanajuato's centre is awash with pink-and-yellow baroque churches, ornate stucco-clad mansions, and opulent, neo-classical theatres, as well as prosaic, colourful box-like homes that crawl up the slopes of the rugged mountains surrounding the city.
A scenic treat at ground level, where you can traverse atmospheric webs of tunnels, twisting stairways, side streets and back alleys, its photogenic quality is best savoured from up high.
My favourite viewpoint lies in the shadow of El Pipila, a giant statue of one of the heroes of Mexico's War of Independence with Spain. From up here, Guanajuato looks like a giant model village, a vast postcard-perfect canvas, a riot of colour, a sublime blend of the natural and the man-made. It's a panorama that's hard to forget.
Down below, Guanajuato has several galleries and museums to peruse - including the ex-Hacienda de San Gabriel de Barrera.
With its lavishly furnished rooms and 17 gardens, designed in various styles from Moorish to Roman, it flaunts the wealth of one leading old silver baron and is a delightful place to while away a few hours.
Though it now operates on a vastly reduced scale, you can still don a hard hat and take a peek inside La Valenciana, once the most profitable mine in Guanajuato (and Mexico). Neighbouring it is San Cayetano Church, adorned with a sumptuously intricate facade and interior.
Despite the mine-fuelled prosperity of the 18th and 19th centuries, most people lived in poverty, subservient to the city's Spanish-blooded elite, who got used to crushing rebellions.
In 1810, in the nearby town of Dolores, a priest, Miguel Hidalgo Costilla, considered "the Father of Mexico", started the Mexican independence movement. Guanajuato saw one of the war's first, and most savage, battles, with local insurgents massacring royalist forces in an old grain storage building (the Alhondiga). They found it hard to break down, but a miner, nicknamed Pipila, set fire to the granary's doors, martyring himself in the process. He's now revered in that mighty statue on the hill.
Today the granary houses a museum covering the conflict and its aftermath. Regrouped, the royalists retaliated in fierce fashion, capturing, and killing, Hidalgo and three of his co-conspirators. As a warning to other dissidents, their heads were placed on the four corners of the granary, where they remained until Mexico sealed its independence a decade later.
If that sounds morbid, it's nothing compared with Guanajuato's Museum of the Mummies, one of the most talked-about attractions in Mexico. In a series of glass cases we find more than 100 mummified corpses, including those of toddlers, a woman who died in childbirth and one who was apparently buried alive.
The leathery bodies were exhumed from an overcrowded Guanajuato public cemetery after relatives were unwilling, or unable, to stump up payments. Macabre and disturbing, the museum certainly isn't for the faint-hearted.
My friend and I had arrived in Guanajuato just after the Cervantino, the 2½-week culture fest that envelops the city each October, drawing hordes of tourists (both domestic and foreign) and leading most hotels and guesthouses to slap "full" signs on their doors.
Post-festival, Guanajuato doesn't sink into a slumber. One of Mexico's liveliest university cities (students account for more than a fifth of its 90,000 population), a youthful buzz spikes the city's cobbled streets, language schools and myriad bars and cafes - day and night.
After dark, a popular pastime is to follow estudiantinas, young, charismatic black cape-clad guides, who lead tourists through Guanajuato, imparting risque jokes and tales of local legends.
While the tours are aimed at Mexicans (or those with a good grasp of Spanish), anyone can join in. Dodge the shoe shiners and mariachi musicians around Jardin de la Union, the tiny laurel hedge-skirted central square, and make a beeline for an estudiantina. For about 100 pesos ($6), they'll give you a porron (a ceramic drinking vessel), which they top up with wine as you wander.
In truth, the women in Guanajuato, though generally easy on the eye, were perhaps not quite as beautiful as I'd been led to believe. The one who stole my heart, in fact, was a 63-year-old grandmother.
Her name was Carmel and she was the landlady of our homely guesthouse, El Hogar del Carmelita. Her bubbly, infectious personality - and her tips of what to see and do - had quickly won us over. Her breakfasts (fresh fruit, omelettes, black beans, fiery coffee and freshly squeezed mango juice) were magnificent, and, in the afternoons, she'd insist we join her in her daily ritual - a shot of tequila.
Our alarm rings at 4am on the day of our departure. We've an early bus to Mexico City and sneak downstairs, trying not to wake Carmel (who, the night before, had handed us a bottle of tequila as a going-away present).
I'm about to write a thank-you note, when I hear a door creaking.
"Hola chicos," says our lovable landlady, in her now familiarly endearing, morning welcome. She's carrying a bag of fruit and freshly made sandwiches.
"For you, chicos," she says, giving us hugs and kisses, and ushering us into the taxi.
As we pull away, I wonder if I'll ever see Carmel, and Guanajuato, again. And I think back to that day on the train in France, and how lucky I was to get chatting to that amorous young couple.
- fact file *
·Deluxe buses for Guanajuato leave more than 20 times a day from Mexico City's terminal Norte. Primera Plus does the five-hour journey for 400 pesos ($29) one way. primeraplus.com.mx
·Rooms at El Hogar del Carmelita are priced from about 550 pesos ($39). hostelhogardecarmelita.com
·An upmarket Guanajuato choice, set in an old hacienda, the Camino Real has doubles from 1450 pesos ($103) caminoreal.com/guanajuato
·For more, go to visitmexico.com