We heard on the radio that terrible things were happening in neighbouring Rwanda. A plane carrying the Rwandan and Burundian presidents had been shot down and violence had broken out. There were reports of massacres of thousands of people and rebel advances.

     It was April 1994 and I was in the small town of Bukoba on the western shore of Lake Victoria, working in the Lutheran Church's construction office. I had been to Rwanda a little more than a year earlier with a group of friends to see the gorillas in the mountains. I had noticed that there were tensions between the Hutu and Tutsi communities, but I didn't realise how serious they were.

     People came to Bukoba and told us that they had seen bodies floating down the Kagera River. Someone had counted more than two hundred an hour while standing on a bridge. We also heard that a large number of people had come to Ngara in Tanzania. They had settled in an area just a few kilometres from the Rwandan border. I got in touch

The truck was travelling along a rocky road that winds around the extinct volcanoes of Bisoke and Sabinyo. Our job was to distribute materials to over a hundred workers who were repairing a 40-kilometre water pipeline that was full of leaks. Somewhere higher up in the forest, the gorillas were living. But they were blissfully unaware of the human activities and concerns. On the back of the lorry were five workers, all Hutus. At a bend in the road, they suddenly spotted a Tutsi walking along the road. One of them picked up a brick and threw it at him. It hit him on the head. There was a commotion and we had to sort it out with the police. The incident was very embarrassing for our organisation, which was completely neutral. We wanted to avoid at all costs the impression that we were taking sides against any ethnic group.

     It was now a year after the genocide and I was working on post-war reconstruction in the north of the country with Åke, an enterprising businessman and Pentecostal from Sweden. He was about 70 years old, but probably had more energy than most. Together

It was dark in Naivasha, so I had to walk slowly and carefully to my tent. Suddenly I saw a large, dark object in front of me. What was it? A bush? A big stone? It was moving. A hippo! It started to chase me and I quickly ran away and hid behind a tree. Apparently I had trespassed on its territory.

     The next morning I took the car and drove to Ol Moran on the Laikipia plateau. When I was working in Kenya, I didn't have much need to go on safari, I saw wildlife every day anyway. On the savannah, giraffe, zebra and elephant were common.

     The plains below Mount Kenya were home to several different ethnic groups: Pokot, Samburu, Kikuyu and Turkana. But relations between them were not always peaceful. Young men from the Pokot and Samburu made a sport of stealing cattle from the other communities. This was a kind of initiation rite, a way of proving their manhood. There were also regular conflicts between nomads and farmers. During the dry season, the nomads would take their cattle to the farmers' ponds and destroy their fields, leading to

What happens to a culture where people never have the opportunity to meet strangers? In other words, a society completely free of cultural clashes. I saw an example of this when I worked for a few weeks in the almost hermetically sealed North Korea. The country was like a ghetto, almost a cult. Nowhere else could you see such large crowds of people marching in unison with such precision. Nowhere else was national independence worshipped with such burning conviction. It was a people of one mind, but it also had the most absurd ideas: 'the Great Leader' Kim Il Sung was elected president for life – even though he was dead. On the anniversary of his death, 'the trees miraculously blossomed in his honour'. At the moment of the birth of his son – the 'the Dear Leader' – inexplicable flashes were seen in the sky and mysterious sounds were heard on a mountain, etc, etc.

     Our hosts took us to attractions that showcased North Korea's successes and achievements. At the Children's Palace, we saw doll-like children playing and dancing with such perfection that I almost suspected they were real dolls. Then we went to the

The office was hot and filled with suffocating cigar smoke. Alfredo and I were leaning over the table, studying papers with drawings and calculations. Suddenly the room was shaken by a loud explosion. 'Per la Madonna!' shouted Alfredo. It was the government troops, who had set up an artillery position near our office and were firing at Tamil Tiger positions inland. Alfredo lit another cigar and we carried on working.

     In Batticaloa, on the east coast of Sri Lanka, I saw a tragic example of how civilians are caught up in conflict. During the fighting, people were forced to move. Our role was to provide them with clean water, latrines and temporary shelter in camps where they could live in relative safety.

     We were getting ready to go to a refugee camp. All of a sudden we heard an explosion above our heads. 'Incoming artillery!' everyone shouted and ran for cover. But there was no real danger, it was just an outgoing shell that misfired a bit. So there was no danger. For us! Situations like that make you very egocentric! Everything was ready and we got

The generator made a terrible noise all night, but we had to keep it on to light the camp for safety reasons. At six o'clock in the morning it was switched off and that's when I woke up – to the sudden silence. I got out of my tent and saw that all the grass, all the trees and all the bushes had turned black and brown. There had been a terrible bush fire in the area the night before. The sea of fire was as beautiful as it was dangerous. But that is normal in the dry season. Luckily the tents didn't catch fire. I was working in a refugee camp in Tanzania, far from the comforts of modern life.

     A conflict in the Congo had caused a flood of refugees to cross Lake Tanganyika into Tanzania. Some distance from the centre was a camp with thirty thousand refugees in need of food, medical care, latrines and water. Each person must have access to at least fifteen litres per day. Fifteen times thirty thousand is about five hundred thousand litres of water a day. We brought water from the spring in eight tankers, but it hadn't rained for four months and the spring was drying up. Transporting water by tanker is expensive in the long run, and

We were driving at full speed across the scorching desert, stirring up a cloud of dust behind us. Ahmed and I and some other colleagues from Sudan had been sent to investigate the effects of a flood on the Nile, and we were heading for the small town of Abu Hamed. It was all sand and rock and there were no landmarks, so the map wasn't much help. After a few hours of driving in the desert, we lost our bearings. The sand was very loose in some places, making it difficult to drive. It got slower and slower and eventually we got stuck.

     We tried in vain to get up. There we were, in the middle of nowhere, and we hadn't seen anyone all day. We worked hard to get out, but the car just kept sinking. Pieces of wood, jacks and tow ropes – nothing worked. After a few hours of work, we ran out of drinking water and realised we were in a very serious situation. We had no way of contacting the outside world and we were in a place where no one normally drives. In the end, we just sat there under the scorching sun, exhausted from thirst and heat.

The helicopter was packed with cement and water pipes and flew over the beautiful landscape of high mountains and deep valleys. There were no roads to Jumla, so all the materials had to be flown in. Anup and I looked out of the window, a little worried. Down in the valleys were the Maoist rebels fighting the government in Kathmandu. It was against international law to shoot at us, but maybe they didn't know that. I dismissed such thoughts and tried to enjoy the scenery instead.

     The Maoists in Nepal had probably chosen a rather unfortunate name to call themselves. Their struggle was not so much about Mao as it was about abolishing the monarchy and the caste system. King Gyanendra was, in popular tradition, an incarnation of the god Vishnu, but in the eyes of the untouchables he was a symbol of oppression. Refusing to work within the framework of democracy, they took up arms in 1998. By then they controlled much of the countryside, particularly in the mountains. Once we landed in Jumla, we loaded the cement bags onto mules – those faithful and