We are charging fast down to the US–Mexican border, lane discipline be damned.

Rick, the boss of the company I work for, his friend Clark, Sami our Sales Manager, and I are visiting San Diego for the week.

We’re here from the UK to attend Society for Neuroscience, a large life science networking event, to try and win some business.

But the powerful smell coming off the temporary carpets and the dull sameness of the 30,000-strong crowd has sapped our will to schmooze, and we all fancy a morning off.

In the evenings, emerging from the conference centre to drink in the fresh air of the waterfront, we’ve been staring out towards the distant lights of Mexico visible across the bay.

It’s a world away, but also very reachable from where we’re stood, so we’ve decided to cross the border into Mexico as we don’t want to pay for another night out in the Gaslamp Quarter.

At the San Ysidro crossing to enter Mexico

The San Ysidro Port of Entry is about a 20-minute drive from San Diego Bay, and gains you passage, on foot or in a car, to Mexico.

This is where our Uber driver is taking us.

He is effusive and brimming with useful advice, giving us the name of a market we can visit in Tijuana (or TJ, as it’s affectionately known, the city on the far side of the border) called Mercado Hidalgo, and details of the current exchange rate for pesos. He even describes the livery of a trustworthy taxi company.

Being a Mexican immigrant, the border crossing is something he does regularly, to take quality goods to his family in Mexico, and bring back medicine that’s cheaper and easier to get hold of on that side and better food.

When he drops us off, there’s no mistaking where the border lies. A hurricane fence hugs America’s vulnerable extremities.

On the near-side of the fence are some fortifications and a few impossibly long freight trains standing idle.

The far side, or as much as we can see of it, is barren scrubland that slopes gently uphill. The urban blanket of Tijuana proper is out of view.

Perched atop the ridgeline are radio masts and satellite dishes, as per usual for an international border. (I’ve always wondered why long-range communications and monitoring devices are needed when your target is right next door.)

Standing around in the car park of the pedestrian border crossing, I look around and take in the rows of shiny Teslas and pickup trucks.

“Quaint” is not usually a word used to describe America, but next to the barricades, everything exudes an orderliness that’s uncharacteristic of this brash country where everyone is a republic of one.

Then again, on reflection, border officials have a way of subduing everyone into acting on their best behaviour. And the ones here are toting fully automatic rifles and SMGs.

The last building in America

The last building you can enter restriction-free before leaving Americaland is:

A burger joint. What else?

I pop inside to take a piss and pass a dollar bill to the heavily-lined man whose life’s work is to guard the toilets.

In the lot outside are kiosks where you can buy pesos on-the-fly. We exchange about $30-worth each—just enough to cover a generous breakfast, taxi fare, and buy some souvenirs if we want.

The buy-back rate is rubbish, so I don’t recommend taking any more currency than you need. Especially for a one-off visit.

With some cash changed, it’s time to walk out of the country.

Entry to the pillbox where you flash your passport and get your bag scanned is gained via a shallow ramp.

A brutal slab of grey concrete crowned with barbed wire squats on top of it, with the word “Mexico” hung in giant metal letters.

I’m sure it gets quite busy, but we’ve caught the crossing on a quiet day. It feels a bit like walking through a tube station on the London Underground, and it’s just as easy.

No one takes much of an interest in us or our reasons for leaving.

It’s on the return crossing that the border officials will swagger about and generally make things as frustrating as they can be—short of us denying re-entry, of course.

And if you like collecting stamps in your passport, brace for disappointment. After a brief riffle through it, mine is passed straight back, and me and my colleagues are free to walk to the Mexican border, just down the hallway.

Walking into Tijuana

We’ve walked about 100 feet through a hallway to get into Mexico, but, when we emerge… Well. This is how Dr Who. companions must feel on their first time travel escapade.

The tranquil high rises and bungalows of San Diego—they’ve gone.

Replaced by a quilt of crumbling, sun-baked alabaster chaos, about as different from America’s neat layout as wattle and daub castles are from the Burj Khalifa.

A throng of taxi touts are scuttling about, offering fares. They are pretty tame compared to how unrelenting they can be in some Asian countries.

After a bit of nervous dithering, we jump into one. It doesn’t match the description our Uber driver gave to us earlier. But none of them do.

He might well have said, “use the ones with no matching fenders.”

“Mercado Hidalgo, por favor.”

Our taxi’s springs and dampers have no will to return to their equilibrium, and we ride every pothole aggressively. The clutch, the gearbox, the seats, and engine look and sound as if they don’t have much left to give either.

After 10 minutes or so, we stop and I pay the fare that I pre-negotiated. (Travel advice for anyone going somewhere a bit exotic: prearrange your taxi fares so you don’t get ripped off.)

Breakfast at Mercado Hidalgo

Mercado Hidalgo is delightful and lends itself well to all the writing clichés.

There are baskets of colourful chillies and vegetables, fragrant dishes of ground spices, and huge smelly cheese wheels.

I’m offered an entire cheese wheel and laugh at the thought of rolling back across the border later on.

The market encircles a central car park. Some bright bunting has been strung up across it.

With a few hours to kill, Rick, Clark, Sami and I take a leisurely stroll around.

Like all walks around markets, there’s little we want or need, but the joy comes from window shopping.

I think the visual texture of big markets is what lends them so much appeal. All the more so when the wares are unusual and presented in bulk.

One store is impenetrable because it's hung with thick bunches of leather sandals.

Another is lined with terracotta pots, stacked nine feet high, like Ollivander’s. What’s impressive is that they are all hand painted and subtly different.

I buy one for my girlfriend to use as a pen pot. My companions refuse to buy anything lest it complicate the border crossing later, which is fair enough.

Once we’ve taken the market in, we choose a place for breakfast.

Some of the taquerías are playing awful screeching music. We pick a quiet one staffed by an ancient woman who looks like a balloon that’s been blown up and deflated again, and what we take to be her granddaughter.

A moustachioed man translates our order for us, and we tuck into delicious tacos and empanadas and a round of cool morning beers.

In the queue back to America

In our taxi back to the border, Clark spots a tobacconist and orders our driver to stop so he can buy some cigarillos to suck on and satisfy his cravings.

The rest of us do a lap of the block in the taxi and pick him up again, smiling away.

We’re also treated to a quick detour lap of the city centre. We catch sight of the Arco de Tijuana, an arch symbolizing passage into Mexico, and drive down a cracked road lined with casinos and clubs where some sex workers are drumming up daytime trade, standing on the pavement in scanty clothes.

I shudder at the scams many of these girls, in cahoots with local gangs probably, pull on desperate and horny visitors.

We’re dropped off at the rear of the America queue. Wait time: 2 hours, give or take.

This queue has developed its own economy.

There are adverts offering discounts (“70% DESCUENTO!!!”) on powerful drugs such as tramadol and testosterone.

The offer is emblazoned across a giant yellow sticker on a billboard, like a discount on stationery. Such “medicines” are available over the counter here.

From the queue, we can see a giant medical complex.

It’s one of the few buildings that looks modern and looked after.

I wonder whether some Americans come across the border for cheap medical services and drugs that they can’t otherwise afford or that their healthcare insurance doesn’t cover.

Likewise, the police cars are fast American sedans, and are the only cars not falling apart.

Police cars and pills. Tijuana’s growth industries.

People with awful diseases and disabilities walk up and down the queue, begging for cash or offering valueless items like chewing gum and tissues in exchange for a few pesos.

A stranger invites us onto a coach to skip the queue. We decline.

As we shuffle closer to the border crossing, I buy some churros from a local vendor and Clark approaches one of the Mexican border guards, draped in guns, to ask about his firepower. He’s a braver man than most.

Close to the border compound, a harassed American woman—also bearing quite a few guns—demands to see our passports.

After checking Sami’s and Rick’s, she frustratedly waves me and Clark straight through with a, “I haven’t got all f*cking day!”

Inside the compound, you can swivel on your heels and peer between two very different countries. It’s surreal.

There’s TJ, looking every bit a Rio favela, in disrepair and without an inch of spare land out of one hangar door.

And out of the other is San Diego, a clean and shiny slice of spacious America, with more than a hint of conspicuous consumption.

American border agents

“Pot? POT?! You’ve brought pot?! Open ya bag, now!”

This is why my colleagues didn’t bother to buy anything in Mexico.

He wants to see the painted terracotta pot I’ve confessed to buying.

I should have just lied and answered “no” to everything.

The customs officer and I both obviously know I don’t have drugs in my bag, but I’m powerless, and have to play his game.

Once I’ve thrown everything back in my rucksack and the grinning officer has granted me passage back to the US, I stand and wait for the automatic gates to open and let me through.

At least I thought they were automatic.

“You have to push the button, Sir.”

Conspicuous consumption

We hail an Uber, and, back on the smooth, wide lanes of freedom, our new driver also ignores the white lines and undertakes every vehicle in sight.

The desperate beggars, great food, and cheap drugs of the queue on the Mexican side of the border are less than 20 miles away from San Diego Bay.

On a drive between the two, you don’t have much time to adjust between the extremes of what people hope and dream to get out of their lives.

Back at the conference centre, the tallest thing around is the mast of the super yacht, M5, owned by the billionaire Texan oil baron, Rodney Lewis.

Estimated value: 50 million USD.

The names of the people in this story have been changed.