In fact Poland have great traditions in gliding. First Lilienthal Gliding Medal in the world was winned by polish pilot Tadeusz Gora in 1938. Take a look at the link below:
http://www.piotrp.de//webde/ and then click Datenbanken and Polnische Segelflugzeuge.
There are all polish gliders. Only Germany have built more sailplanes (but polish are much more prettier in my opinion :) I consider that the best 15-meter glider in the world is the polish Diana II currently.