By Prof. Garcia-Ruiz,

I had the honor of delivering an invited lecture at the Annual Meeting of the Belgian Society of Crystallography, which this year, for the first time, was held not at the Belgian Academy of Sciences, as usual, but at the ancient and prestigious Leiden University in Flanders.

The choice of Leiden was deeply meaningful: the following day marked the ceremony of appointment as Emeritus Professor of my friend and outstanding crystallographer Luc van Meertvelt. On this very special occasion, I also had the privilege of giving a lecture to the colleagues, relatives, and friends who gathered to celebrate him.

Luc and I share a longstanding friendship, built on our common dedication to promoting Crystallography in developing countries and among school and high-school students all over the world.