A Condorcet domain is a set of linear orders such that, if voters express preferences from this domain, they never run into the Condorcet paradox and their majority relation is always transitive. Classification and description of Condorcet domains, especially maximal ones, is one of the most interesting combinatorial problems of social choice. We have discovered a close connection between Condorcet domains and median graphs (grid graphs and trees are examples of these). I will also demonstrate a close relation of Condorcet domains with Bruhat orders and generators of subgroups of S_n. This is a joint work with Clemens Puppe (Economics, KIT, Germany).