  On the occasion of centenary of superconductivity discovery I remind some
facts from the first period and attempts to understand the phenomenon. It turns
out that most famous physicists of the first half of XX century have tried to
solve the puzzle. Bardeen, Cooper and Schrieffer succeeded in 1957. BCS theory
successfully described all known facts and offered new predictions, which soon
have been confirmed experimentally contributing to the widespread acceptance of
the theory. New discoveries of the last quarter of the century put new
requirements for the theory. It turns out that simple BCS model is not enough
to understand new unconventional or exotic superconductors. Even though the
superconductors have found many important applications in various branches they
have not yet fulfilled the hopes. In spite of that the scientific studies of
superconductors develop vividly and fascinate new generations of physicists.
