The last trench in the ancient Iberian stand-off between Moors and Christians, Melilla has been Spanish since 1497, when the conquistador Don Pedro de Estopinan and 500 men seized the rocky outcrop, built a huge fortress and then extended the city boundaries to the range of a cannon-shot.
As the Moors had been expelled from the peninsula only five years earlier, Spain established a string of fortresses along the Moroccan coast to ensure it would never again be invaded from the south. Six Spanish specks remain, but Melilla and Ceuta are the only ones anyone has heard of.
It may be a Spanish city flying the starred blue flag of Europe, but when you arrive on the domestic flight from Madrid lands at Melilla airport, it is the baked earth of Africa that assails your nostrils.
Antonia and I jumped into her car and bowled along handsome Art Deco boulevards - laid out with palm trees in the early 1900s by the Catalan, Enrique Nieto, a disciple of Gaudi - to the border town of Beni-Enzar ("son of a Christian"). The journey took 10 minutes, during which the torpor of a blistering morning gave way to the hectic bustle of traders on the move.
Men, women in gigantic flowing jellabahs and children walked purposefully, laden with enormous burdens. A mule, its eyes protected from the desert sun by folded cardboard popped over its ears, pulled a trap, creaking under the weight of a refrigerator. Similar burdens wobbled on bicycles and on backs that were bent double.
Moroccans lined up outside shops along the frontier road, buying clothes, crates of soft drinks, biscuits, kitchenware and nappies. "All these goods come by boat from mainland Spain, but only about 20 per cent stay in Melilla," Antonia said. "That French company that makes cheap glassware sells more to Melilla than to Madrid and Barcelona put together. Only 65,000 people live here, but the whole of Africa is the market.
"Contraband," she adds."
At the border, fearsome spiked-metal platforms lie ready to be dragged across the path of any transgressing vehicle, but human traffic passes without hindrance. Moroccans from the surrounding Rif area, the country's poorest, can come and go freely so long as they are home by evening.
There are frowns at the unexpected appearance of a northern European, but Antonia speaks through a slit in the wooden border post to an official who is invisible behind a dusty window. "I know him," she explains. She takes my passport and returns within minutes, bearing two flimsy forms - exit and re-entry visas - fluttering in her fingers.
Once across, I am transfixed by the squat, pastel-washed houses that dot Morocco's parched hills. But Antonia spots something else. "Look, the Guguru is on fire." Flames rip the mountain top ahead of us. "This happened last year and the Moroccan authorities called on Melillan firefighters and police for help, because they don't have enough water. The smugglers had a wonderful night with no one watching the border."
A mile on, police check the taxis for contraband. But the passengers with their burdens have already disembarked. The empty taxis drive on and wait for their passengers to rejoin them.
At Nador, we plunged into the souk, through alleyways of up-ended sheep's heads, windpipe and horns that curled up to meet us, past conical heaps of spices, fruit and vegetables arranged geometrically, carrot by carrot, fig by fig, to what Antonia called "El Corte Ingles", after Spain's biggest store.
In the stalls of jeans, trainers, women's suits and men's shirts, the labels said "Made in Spain" and the prices were knockdown. If I inadvertently jostled someone, they apologised profusely in fractured German. We couldn't enter a cafe, of course, so took a cola and a dish of mint-and-almond pastries at the five-star hotel.
The road back north runs alongside the abandoned "ore railway" that used to bring iron from the Rif to Melilla's portside. We stopped at the beach, where Muslims, Christians, Jews, Hindus and Gypsies lolled and strolled together.
The picture of racial harmony was jarred only by the burnt remnants of a union flag, testimony to Spanish disappointment over a Wembley football match the day before.
Finally we stepped into the cool Spanish home of Antonia's mother for lunch. She had prepared her speciality: couscous, followed by mint tea.