"Tropenliebe" tells the story of the Basel Naturalists and Cousins Paul and Fritz Sarasin. As friends and lovers they travelled through british and dutch colonies in Asia around 1900. Their research in Ceylon turned them into pioineers of German 'race sciences'. In Celebes (Sulawesi) their research paved the way for the Dutch Colonial Army to invade the island. In Switzerland the Sarasins counted as the most influential scientists from their generation. This story about love and violence in Southeast Asia sheds new light on german and dutch colonial history, and on the history of Switzerland, a country that long believed to not have a colonial history at all.