civilisation, having in mind the catastrophes caused by Man's activity; we may also look at the examples showing the development of knowledge and the skills derived from it, which enable the elimination ofthreats and, at the same time making Man's life richer. It is not possible to make an in-depth analysis of the phenomena mentioned above in a short opening speech of the Congress. Nevertheless, I would like to share with you an optimistic reflection. I think that we can observe two trends in the development of our civilisation - good alternates with evil, environmental threats with the hope for their overcoming, and events swing to both sides like a pendulum in a clock.