Fill in the Blanks PolandOnline version How much do you know about Poland? by Barbara Jurzyk 1 Republic population largest North has celebrates member Russian Germany Czech million May bordered Constitution Kaliningrad Ukraine East Poland a of approximately 38 ( 2014 ) , making it the sixth European Union . Poland is by to the West ; the and the Slovak Republic to the South ; and Belarus to the ; and Lithuania and the enclave of to the . The principal centres of population are Warsaw , Krakow , Wroclaw , Lodz and Poznan . Poland its Day on 3 .