In the summer of 1929 Andrei Kolmogorov and Pavel Aleksandrov visited lake Sevan in Armenia and lived in a cell in the monastery on the island. During about a month they not only enjoyed the beauties of the lake, but actively continued their research, Alexandrov working on "Aleksandrov-Hopf" (P.Alexandroff, H.Hopf, Topologie, Berlin, 1935), Kolmogorov on the paper "On analytic methods in the theory of probability". Both mathematicians mentioned Sevan in their memoirs many decades later. They visited also other sites of Armenia and climbed Mt.Aragatz.