I am one of a small group Segway-ing along Beach Street by San Francisco Bay. We're quite the centre of attention;

pedestrians seem to like us, but judging by the hooting of horns, motorists caught in our slipstream aren't so keen: our top speed is eight miles per hour.

Yet we're soon off the tarmac and on to the pier, where we revolve our hi-tech steeds for a world-beating 360-degree view of the Golden Gate Bridge, Alcatraz and the undulating sprawl of this Pacific coast city.

We are taking a tour with the San Francisco Electric Tour Company. Our guide, Jos�, leads us along the waterfront to the Golden Gate Bridge, revealing points of interest via walkie-talkies. We look like tourists with a capital T, but who cares? This is a fun way to embrace a new city. After all, why go halfway across the world and miss the iconic sights of this great Californian destination for fear of looking like what you are: a tourist? I positively craved my first glimpse of the Golden Gate Bridge and couldn't wait to take the cable car over Nob Hill. And, if I hadn't run out of time, I would have surely taken the boat to Alcatraz, followed in the tyre tracks of Steve McQueen down Lombard Street, got on the beat of Jack Kerouac in Russian Hill, hit the '60s hippie trail in Haight-Ashbury and cruised around The Castro, the city's gay quarter.

Yet to get a real sense of a new city you must mix the old with the new. So, I'm off to Mission, the working-class Hispanic quarter, which is succumbing to gentrification at the hands of northern California's young dotcom millionaires seeking an alternative to the established rich neighbourhoods.

It's typical of the kind of neighbourhood you can find in cities around the world, sought out by the more inquisitive tourist who wants to get a glimpse of ordinary life and find out what the locals judge to be hip and happening.

And this latest district to explore in San Francisco is also the oldest. For, long before the dotcom merchants arrived, the Spanish were here. They established the town that would become the city in the late 18th century with the construction of Mission Dolores (then Mission San Francisco de Assis, hence the city's name), one of 21 religious outposts on California's Camino Real, which stretched from Mexico to Sonoma, the northern border of Spain's empire in the Americas.

It seems such a grand role in history for the simple adobe building in front of me, the first stop on my tour of the neighbourhood. My guide is Jean Feilmoser, who runs J Walks. She's a native of Mission, but was pushed out by soaring property prices. But before she shows me how the area is changing she wants me to appreciate where it started.

So we take a walk within the mission's four-foot-thick walls, where its outer simplicity is belied by inner glories.

Above us, redwood beams lashed with rawhide bear vivid decorations just like the ones applied by workmen from the local Ohlone tribe who put them up. The wooden columns adorning the side altars are painted with great skill to resemble Italian marble. But the focus is the reredos, an elaborate gold altar brought here from Mexico.

This was once the only stop on Mission's tourist trail. But Jean has always known that this area holds more to entertain outsiders like me. So we head for Mission and Valencia Streets, the district's two main arteries. These parallel thoroughfares are only two blocks apart but they neatly reveal the neighbourhood's split personality.

Mission Street is a tatty drag of bargain shops and grocery stores, busy with people going about the daily grind. It's the edgy side of the neighbourhood. A few years ago, most outsiders would have only ventured here to try the legendary burritos.

Yet even here there are signs of change.

One of the first trendy businesses to open in Mission was Foreign Cinema, at No 2534. It certainly ticks my eccentric box:

it's a fine-dining restaurant-cum-picture house, where you can tuck into half a dozen Fanny Bay oysters while watching Breakfast at Tiffany's. It has a decent gallery showcasing modern art and a swish bar serving a nightly menu of DJs and cocktails.

But you'll find many more of these new ventures on Valencia Street, the frontline of gentrification, where traditional Mexican businesses are being edged out by bijou boutiques and trendy eateries. The bright young things on the sidewalk are dressed down, with a leisurely air of nowhere to go.

Jean points out a cute clothes boutique and a shop dedicated to the sale of shiny 33beads. We grab a cappuccino at Ritual Coffee Roasters, which invites us to "Revolutionize your daily ritual". But to assume what's of interest here is confined to an alternative shopping strip is to miss the point. These new shops, caf�s and restaurants are drawing visitors to the neighbourhood, but what they will inevitably discover is that its real treasures have been here all along.

Jean takes me away from the main drag and into the sidestreets to see these gems; the fascinating, vibrant murals that celebrate the struggles of ordinary people. There are hundreds of them, painted on the sides of shops, schools and community centres. Some of the best can be found on Balmy Alley, a cut-through between 24th and 25th Streets, where every inch of wall, fence and garage door is decorated with tales of hope and despair.

The rich tradition of counter-culture is still the freshest story in this city.

FURTHER INFORMATION San Francisco Electric Tour Company (001 415 474 3130; electrictourcompany. com). J Walks (00 415 979 4171; jwalks. com). San Francisco Convention & Visitors Bureau (001 415 391 2000; onlyinsanfrancisco. com).