At IPT 2017 towers made out of gelatin blocks were constructed by many teams (problem 3, LEGO tower). The problem reminds me of a problem, that was played 4 years earlier, when I was a member of the Russian team “Wolfram”. These problems partly share the mechanisms of column destruction, so I would like to share my 4-years-old presentation. I hope you enjoy it and find it useful – my “Tallest sand castle” report was awarded by the “Best report” prize of the tournament 2013. Later it was published in a popular-science journal Potential (Potential 2015, no. 11, pp. 64 – 77, ISSN 1814-6422, in russian).