The Poland of after WWII has a similar area with the Poland of before WWII, but it has moved a lot towards West.
So the winners have been the Russians and the losers have been the Germans.
Poland was lucky because its large territorial losses to the Russian invaders have been somewhat compensated with territories taken from Germany.
The other Western neighbors of Russia have been much less lucky. The larger neighbors (Finland, Czechoslovakia, Romania) have lost large territories stolen by Russia without any compensation, while the smaller neighbors (the 3 lesser Baltic countries) have been incorporated completely in the Soviet Union.
I have written "the 3 lesser Baltic countries" because prior to WWII Finland was counted as the 4th Baltic country, since all 4 countries occupy the Eastern shore of the Baltic Sea, and they all form an enclave between Germanic-speaking people to the West and Slavic-speaking people to the East (the main languages in Finland and Estonia are Uralic, while the main languages in Lithuania and Latvia belong to the Baltic branch of the Indo-European languages).
For example, in the Ribbentrop-Molotov pact from 1939, the Russians have written explicitly their intentions to occupy all the 4 Baltic countries (Finland, Estonia, Lithuania and Latvia) and also Romania, and the Germans agreed with this, while the Russians agreed that the countries of Western Europe should belong to Germany.
With regards to eastern territories, Poland may reclaim some of those right now if it is insistent :)
First of all, it was not Russia but USSR who took your lands; second, USSR did not give these lands to Russia (even in the form of RSFSR) but to other russophobic eastern european countries.
You are grown-ups now. Sort it out between yourselves.
They (USSR was Russian-lead) were literally allied with Nazi-Germany and agreed to split Europe with them. They executed 20000+ Polish people in Katyn alone.
So?
Dear krzyk! Do you consider jews people?
Russians (USSR, potato-potato) at that time were exterminating most of people that had any kind of education - because those were potential "traitors".
Most Jews were intelligence class, which was considered enemy of the "working class".
Indeed, many of eastern european countries used the period of Nazi occupation to get rid of as many jews and gypsies as possible. I'm not going to point fingers but you should double-check your history.
Not countries, but stupid people. There a lot of those that envy others.
Same happened in Soviet occupation but for different reasons. Either way EE was f**ed. Check why there were so many Jews in Eastern Europe when comparing to Western (they found save place here because they weren't so much persecuted like in the West).
Or maybe lets see what happened in Ukraine which was under USSR occupation before the WW2 - Holodomor which resulted in up to 3 - 5.5 million people dead, which is close to Holocaust numbers.
When Soviet army marched everyone hid their daughters and wifes, to this day our grandparents tell stories how they were in the basements, or escaped to the west just not to be taken by Soviet soldiers.
On the other hand some parts of Poland were consider by Nazis as their land and they didn't rape or kill citizens, but they had obligatory conscription of capable man - many of them tried to hide and died if they were found.
I would just argue that Nazi-germany's industrial-scale extermination of jews, homosexuals, handicapped etc is still worse. Anyway - it is arguing semantics and definitions. :)
Somehow people forget that the Nazis wanted to kill or enslave all Slavs[1] within their "lebensraum" territories.
[1] They also considered Estonians and Finns as "Mongoloids" and as such subhuman although both were elevated to "Aryan" status following the winter war.
The Belarussian / Polish border today is almost exactly the border between Kingdom of Poland and Grand Duchy of Lithuania within the Polish–Lithuanian Commonwealth. So "historically eastern Poland" is not right there. Some like to think of the whole Commonwelth as Poland, which really dominated there. But in this case whole Belarus and Ukraine are "eastern Poland".
That's what poles tried to restore when got chance to recreate their state after WWI, as I understand. The full commonwealth. But only got to the borders we know as the pre-1939 Poland.
BTW, Ukraine is mostly the part of the GDL annexed by the Kingdom of Poland during the Union of Lublin. The todays Belarus / Ukraine border goes by this line.
There are overlap maps in wikipedia: https://en.m.wikipedia.org/wiki/Polish%E2%80%93Lithuanian_Co...
Going deeper in history of GDL, Russia and Poland uncovers more.
[0]: https://commons.wikimedia.org/wiki/File:GUS_languages1931_Po...