The cost of our success is the exhaustion of natural resources, leading to energy crises, climate change, pollution, and the destruction of our habitat. If you exhaust natural resources, there will be nothing left for your children. If we continue in the same direction, humankind is headed for some frightful ordeals, if not extinction.

My parents, of Belgian-German extraction, were Belgian nationals who had taken refuge in England during the war. They returned to Belgium in 1920, and I grew up in the cosmopolitan harbour city of Antwerp, at a time when education in the Flemish part of the country was still half French and half Flemish.

Due to these various circumstances, when I entered the Catholic University of Louvain in 1934, I had already travelled in a number of European countries and spoke four languages fairly fluently. This turned out to be a valuable asset in my subsequent career as a scientist.

My education, according to the tradition of the Jesuit school which I attended, had been centered on the 'ancient humanities', and I was strongly attracted to the more literary branches.

Our investigations were very fruitful. They led to the discovery of a new cell part, the lysosome, which received its name in 1955, and later of yet another organelle, the peroxisome.

When, in 1949, I decided to join the little band of early explorers who had followed Albert Claude in his pioneering expeditions, electron microscopy was still in its infancy.