Sometimes, when you travel, circumstances don't just smile - they grin at you, serving up a delightfully serendipitous treat.

So that's why I am standing here now - six rows back from the choir, in this huge basilica in Lyon, France, singing a hymn in a language I cannot speak. The words are simple, and I can get the drift of the meaning. But I am very aware that I am lacking a vital accessory. A child.

Around me are dozens of them, most with their mothers, grandmothers, aunties and big sisters; some with their fathers too. The singing balanced on the deep tones from the pipe organ resonates against the richly mosaic-ed walls and floors, that in turn sparkle with reflected light from the votive candles, the bunched tapers, and the bright faces of all those youngsters, scrubbed up for this special occasion.

The service, I am told on the song sheet on my seat, is the Presentation of the Children, and I lucked in on the beginning of it simply by taking the funicular railway (one of just a handful in France) after lunch from the old town and joining the stream of people hurrying across the forecourt into this ornate white neo-Byzantine building that dominates the city and its skyline.

Built in the 19th century, mainly using subscriptions raised by the local Lyonnaise people, the speed of construction - a rush job that took a mere 30 years - belies the intricacy of its execution. There should be a warning sign posted on those heavy doors, for entering the building (itself a confection highlighted by a golden angel at the tip of the tower) is enough to make even the most hardened cathedral-junkie gasp.

Every surface - that's every surface - is richly adorned; the walls with gold embroidered mosaics that trail and intertwine connecting Scripture with daily life; the floor with less colourful yet stylish tan, black and white tiles. The glorious stained glass windows behind the altar, which would earn a good paragraph in any guidebook, are outshone by the intensity of decoration in the vaulted interior. The light they allow to enter serves only to illuminate those walls.

And while some visitors are less than complimentary about that building ('gaudy' decries the Eyewitness Travel Guide to France, 'all too conspicuous' belittles the Blue Guide) I found as I wandered around this surprising city, that Lyon (no s, please, that's the anglicised spin on the name) is like that. Full of hidden beauty, and intriguing discoveries; maybe not to everybody's taste, but with a surety and panache born of centuries that hardly cares.

A good way to see the city is in these vintage Citroens

For this was basically an artisan's town. A weaver's centre for centuries, and a base for silk merchants, guilds and commerce since the Middle Ages, with the heyday of the silk industry lasting from the 17th century until the present day, Lyon is still a vital city with an edgy interest in fashion and art. The Musee des Tissus displays fabrics in the 18th century Hotel de Villeroy and traces the complex history of weaving, while a special walk to several places in the Croix Rousse area gives a peep into the world of the 'canuts' or silk weavers.

One anecdote suggests that the worker's distinctive name, canuts, came from a contraction of the cry 'voici les cannes nues' or 'here are our bare sticks', from the fact that during the Industrial Revolution, the impoverished workers were forced to even sell the gold and silver trappings from their own walking sticks in order to survive.

Located as the northern bastion of the Rhone region, Lyon has a toe, figuratively, in the waters of two major rivers: the Saone flowing down from Burgundy, and the Rhone that rises to the east. This happy merging makes Lyon both a strategic river port and a major industrial city.

Wandering the old city of Lyon, though, you are struck by its similarities to Paris. Like a mini version of the capital, here there are limestone apartment buildings embroidered with wrought iron balconies; 'a left bank', the old town, where students grab a crepe and a coffee, or maybe frequent the trendy Thé shops, drowning exam nerves with a quick cup of vervain or chamomile before racing off to their next class; plus there is an Opera, many museums, and a cathedral. And of course repetitious arched bridges over both rivers, either of which in the right light may resemble the Seine.

In fact Lyon, with its population of between 500,000 and a million inhabitants, depending where you begin and end counting, has everything you could need in a city. As France's second industrial city it is now also valued as a UNESCO World Heritage site, chosen in 1998, and cited as 'an outstanding illustration of the progress and evolution of architectural design and city planning throughout the centuries'.

Little wonder as Lyon has had urban settlement for over two millennia. Ancient Lyon, called Lugdunum meaning 'hill of the crows', was founded in 43BC and was initially the capital of the Western Roman Empire. Remains of this settlement are still evident on Fourviere hill. The Croix-Rousse, Vieux Lyon and Presqu'ile peninsula are at the heart of Lyon and share a unique architectural continuity.

As the centuries rolled. the Middle Ages saw Renaissance development in the old quarter of the town, and by the 19th century an industrial 'village within the city' had evolved to accommodate to burgeoning silk industry, as well as the establishment of the city's major thoroughfares. Recently avant-garde structures such as the neo-classical National Opera, a controversial barrel-shaped glass and steel building, and a revamping of some of the public squares have attempted to bring the city into the new century.

For such a hard-working industrious place, a surprisingly recurring theme throughout Lyon is its puppets. A shop next to the creperie in the Place du Change where I enjoyed a speedy galette (tomatoes, cheese and ham topped with a just-set egg) was unfortunately closed until the next day, but I ogled its wealth of marionettes through the window. On a street corner nearby, a Punch look-alike advertised a Guignol show. This plug-ugly fellow's face pops up all over the place and somehow typifies the place: the underlying belief that all will come out right, somehow, in the end if you do the right thing.

Created by the Lyonnaise puppeteer, Laurent Mourguet, in the 19th century, Guignol (said to have been named for and modelled on a real-life silk weaver) is now the most well-known puppet in France. This not-too-bright character is always in a scrape, always the under-dog, but eager to please and be of use. With his wife, Madelon, and mate Gnafron, Guignol is now synonymous with street theatre throughout the country, and there is even a museum devoted to his history in the old part of Lyon.

In recent years Lyon may have been superficially eclipsed by big-sister Paris, 450 kilometres north, but the Guignol ethic exists. Fun on the surface with a serious underbelly of work and dedication; the belief that you can have your amusement, but there should be a moral; that beauty is OK, but you must work hard and invest in it to achieve it.

As a reality check, I only had to remember the basilica's gold-shot mosaics and the light in those children's eyes to realise that 21st-century Lyon still operates pretty much that way.

- Sally Hammond