What is the most important thing to know about Jan Kammann? He laughs and gives the question a little thought: "That I am very open-minded about the world. Every day, I have a lot of fun getting to know people and understand their circumstances." A short pause. "And also telling a joke now and then," the 39-year-old says, laughing some more.

For six years, Kammann has been teaching English and geography at the Gymnasium Hamm, a secondary school in Hamburg. Pupils at this "Europaschule" — a type of school in several German states that has an intercultural curriculum and innovative teaching methods — come from all over the world.

When they arrive at his school, Kammann says, they are often in a rather vulnerable situation: "Neither parents nor pupils speak a word of German. They have to put themselves at our mercy." People often think it is easy to integrate in Germany, Kammann says, but many things are different in other countries.

To better understand his students, Kammann took a voluntary leave of absence and traveled for a year through their native countries in Europe, Asia, Latin America and Africa. He wrote a book about his experiences: "A German Classroom: 30 pupils, 22 nations and a teacher on an around-the-world trip." Some of his experiences are detailed below, and in the gallery above.

Read more: 40 years on: African contract workers who came to Germany and stayed

Bulgaria: Little-appreciated abroad

Kammann relates how one pupil always came back to school days late after holidays with her family in Bulgaria. She said it was because of the lengthy bus trip. During the summer holidays, her teacher got on the bus himself and was amazed at how long the journey took.

The bus picks up Bulgarians across Germany who work as seasonal farmhands, on construction sites or as care givers. These are people whom many Germans don't really consciously perceive, Kammann says. "But our economy would probably not function without them."

After two days on the road, interrupted by a breakdown, Kammann arrived in the capital, Sofia, completely exhausted — and his pupil had to travel on a further 500 kilometers (311 miles) from there.

Read more: Germany's migrants: Wooed and discriminated against

Russia: Reconciliation must continue

Kammann regularly encourages his international pupils to present "newsflashes" in which they report what media in their native countries are saying. His Russian pupil gave a talk about the "fascist intervention" by Western Europe in Ukraine. She spoke to the class about fascism and the many Russian victims at the hands of German aggressors during the Second World War.

During Kammann's trip to Russia, he visited a German-Russian exhibition where he listened to recordings of German soldiers cynically describing how they murdered civilians. Reconciliation has to come from both sides, Kammann says, and you have to keep at it.

Iran: Learning new cultures

During many conversations with Iranians, Kammann realized how Eurocentric his view of the world is. An Iranian sociologist who knew a lot of European cultural history asked him if he was familiar with any of Iran's great intellectuals. Kammann couldn't name one. He decided to learn more about other cultures and integrate it into his teaching.

South Korea: Respecting food culture

Kammann had noticed that a female pupil from South Korea became uneasy when her classmates loudly discussed conflicts. During his stay in South Korea, he saw how much more carefully people there treat such topics.

He describes how, in a restaurant, he started kidding around and laughing loudly. Later, he says, he realized that his behavior could have been understood as a criticism of the waiter or the food. He says he was very sorry — in fact, he very much enjoyed the variety of Korean cuisine and even enrolled in a cooking course. Food promotes communication; Kammann also asks his pupils about the culinary specialties in their homelands.

Ghana: Refresher course on colonial history

Kammann's pupil Jeffrey was born in Ghana's capital, Accra. He was delighted that his teacher traveled to his native country and those of his fellow pupils. "I don't know any teacher like him who would do such a thing," Jeffrey, now 19, told DW.

Jeffrey says he finds it annoying that there is so much generalization in Germany about Africa. Every country there is different, he says, but there is little heard about it in school.

He had recommended that Kammann learn about the slave trade in Ghana. In Cape Coast, the teacher visited a museum that explained how colonial powers first carried off gold and tropical wood, and finally people from West Africa as slaves. Kammann was shocked by the cruelty.

Integration in the classroom

Stefan Behlau, who heads an education association in the German state of North Rhine-Westphalia, says Kammann's approach is "interesting and enriching." However, Behlau believes that kind of hands-on education is very time-intensive and thus very difficult to translate onto a larger scale, particularly given the current lack of teachers in Germany.

"If we had enough personnel and time, integration in school would long have ceased to be a political issue," he says. "What is important is to look at where pupils are starting from, not only for the sake of cultural and linguistic integration, but also social integration."

More world trips coming?

Kammann says that since his trip, he respects his pupils even more for their achievements in learning German and the way they adapt to a new culture. He says he feels very privileged to hold a German passport. He has brought back many questions about poverty, wealth, trade and fairness that he includes in his teaching.

He can easily imagine traveling to his pupils' native countries again: "I have travel guides for 45 countries — enough material for a lot of world trips."

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