Where do you discover the heart of a city? In the most unexpected places, says Hilary Bradt, founder of the acclaimed Bradt Travel Guides. Use her tale from Namibia's capital as inspiration for your own travel writing.

Windhoek is an orderly city. The traffic lights work; modern houses with well-kept gardens line the suburban streets; the stores on Independence Avenue are full of desirable items; the restaurants can compete with any city in the world. And that was the problem. I found it too bland, too predictable. It lacked the cheerful chaos of a typical African city; there was nothing to turn a morning's sightseeing into a memorable experience.

Of course, the real Namibia couldn't help intruding at times. The Herrero ladies dressed in voluminous Victorian dresses with what looked like giant bananas on their heads were certainly special, as were the German colonial buildings, most notably the city's main landmark, the Lutheran Christus Kirche. Standing on a hill, surrounded by green lawns and palms, this is a gingerbread church of orange sandstone trimmed with white, built to mark the successful suppression of a native rebellion.

It was completed in 1910, 20 years after Germany took control of South West Africa. Inside are rows of plaques inscribed with the names of the Germans who died in the uprising: more than 1,500 of them. What we are not told is that among the indigenous people, the Herrero, about 65,000 were killed, nearly 80 per cent of the population.

As in so much of Africa, the church has played a prominent role in this city, both historically and in the present day. Back in the 19th century, the Rhenish Missionary Society strove to improve the lives of the local people and German religious organisations are still active in Windhoek. One such place is the Bernhard Nordkamp Centre in Katutura. The name is said to mean "where one does not wish to live" in the local language, and it's Windhoek's largest township. South Africa controlled Namibia for more than 70 years, and this legacy of apartheid is still a repository for the human detritus of prosperous Windhoek.

Katutura is not a sad place; it has its own vitality and culture. And it has MaryBeth Gallagher. MaryBeth is a larger-than-life American who came to Namibia in 2005 because "I like to have bare arms, wear shorts and ride a bike". She is a volunteer for Maryknoll, a US-based Catholic organisation, and her calling seems to feed directly into her energy centre like a glucose drip. I'd contacted her through the website stuffyourrucksack.com, and at her request our group of eight brought footballs, children's books, and lots and lots of "sharpies" (Magic Markers). In return she would show us the centre.

We were still unpacking when MaryBeth bounded out of her borrowed car, threw open the boot and said: "Hi, I wanted to catch you all before you'd had time to buy souvenirs. Come and look. Aren't these great? " About 30 black dolls smiled back at us. "They're Miriam's. She was part of a women's co-operative that made these dolls but it all went wrong." MaryBeth pulled a face. "Some of the women were caught stealing and the whole thing collapsed. Miriam told me that if only she had some money she could start up on her own. I trusted her, and lent her 1,400 Namibian dollars [£100]. We bought a hand-operated sewing machine – she has no electricity – and the fabric. And you know what? She paid me back in two weeks!" With MaryBeth as her marketing manager I'm not surprised. Miriam's Big Mama dolls are now sharing a bed with several members of our group and are on sale in Europe and the US.

"OK, let me tell you about the centre." We were now in the car with MaryBeth talking unnervingly over her shoulder as we drove to Katutura. "The kids come here after school for a bowl of soup and some bread. Often it's their first meal of the day. Yes, they do go to school. Their fees and uniforms are provided by Catholic Aids action." That was when we learned that the centre offers Aids testing and support. In Namibia, the disease affects about 20 per cent of all pregnant women, and most of the children attending the centre are Aids orphans.

"So most of them don't have a real home to go to," she continued. "That's why we run this after-school programme. At first, I thought we'd just help with their reading, writing and maths. But then I saw there were bigger problems. One of the girls could write her name but couldn't spell it out for me. She'd never learnt the alphabet. When I played bingo with them, I noticed that some of them had never been taught to count."

It was in those early days that MaryBeth realised that the children would learn more easily through games and play than a classroom situation. "Yeah, I can't wait to show you my book!" She'd told me earlier about this project. "It Costs Almost Nothing" describes a range of toys and games made out of recycled materials. Things like bottle tops, tin cans and cardboard. That's why she needed the sharpies. The local felt-tipped pens weren't robust enough for making puzzles and board games.

At last her eyes were on the road. "Are you prepared for this?" she asked. "I'll just leave you to do your own thing." "Oh yes," we lied. We'd agreed to spend the afternoon at the centre but in my naivety I'd expected an organised tour. We swung left through an open gate and into a courtyard furnished with picnic tables, and brightened by the murals painted on the white walls of the activity rooms and clinic. Shoals of shrieking children swirled round the car like fish, and MaryBeth was soon swallowed up in the mayhem.

We stood around feeling stupid. Then I felt a tug at my hand. "Hello! My name is Ben." A small boy was thrusting an exercise book into my hand. He was learning German, a language I happen to know. We counted to 10 and beamed at each other. I was beginning to enjoy this. "Do you play football?" My self-confidence evaporated. "No. Do you?" "Yes, and so does MaryBeth. She plays goalie." He trotted off to join a more rewarding member of our group. It was a toss-up between Richard, who was talking about Manchester United, and Nick, whose digital camera screen brought screams of delight as the children recognised themselves.

Two girls showed me how to play Etosha, a home-made version of Battleship. I could see that searching for an opponent's animals was better than trying to sink one another's battleships. It uses mathematical skills – which explains why I was no good at it – and also teaches city kids about wildlife.

Suddenly, MaryBeth was with us again. "Hey, did I tell you about the swimming excursion? We took a bunch of kids to the municipal baths. They agreed to let us come in for free. How many came – 565!" She shrieked with laughter. "The woman behind the counter just couldn't believe it. She was on the phone trying to complain, but meanwhile we just filed past the security guards until everyone was in.

"Oh no, they can't swim. Thank goodness we had plenty of volunteers to watch them. We spent the whole day there, with the kids just yelling with delight, and several told me afterwards that it was the happiest day of their life."

It was time to go. As we drove back to our hotel MaryBeth asked: "Did little Salome offer to braid your hair? I thought so. She's one of my favourites, but we've had our tussles because she simply wouldn't read. It was frustrating because she's clearly very bright. But the other day I was reading a text message on my cellphone while Salome braided my hair. She leaned over my shoulder and started reading it to me. I just dropped the phone and hugged her, saying: 'You're reading, you're reading!' She was so happy that I was happy. Then she asked to borrow a book to take home to read to her granny." MaryBeth grinned at the memory. "You can see why I want to stay here."

After Windhoek, we toured Namibia and, like all tourists, were bowled over by the wildlife and scenery. I'll never forget those vivid desert colours and the medley of wild animals. But when we talk about the trip we always return to that wonderful afternoon in Katutura, Windhoek's beating heart. We remember the cheerful chaos and recall those beautiful laughing children, and the stories of their tough lives. And when I go to bed in chilly England, there's Big Mama smiling at me from my pillow.