I've spent quite some time in Poland during the summer of 2019, while in 2018 I just passed through. This is a huge country, and wherever I went I could feel how a country can rebuild from a troubled history.
Today, Poland is part of the EU which makes things convenient. EU roaming works, the only difference is that they don't use the Euro. But there are ATMs everywhere, cards are mostly accepted, I had no issues with Zlotys.
Maybe it's due to its own money but Poland is slightly cheaper than its Euro-using neighbours. Especially in the Baltics, people complained that when they introduced the common currency prices went up significantly.
Getting around Poland is easy. There are trains going to most places, and there are buses going around. As for trains, there are TLK, IC, and EIC ones, in this order in regards to prices. You can browse the timetable, buy tickets online and you don't even need to print anything. Just show the QR code on your phone along with your ID card and you're done.
My impression was that the country has a lot of greenery. Not just it's huge and thus it has space between the cities, but also there are many parks and green spaces inside populated areas. Becasue of this, it is usually a pleasure to walk to different parts.
Milk bars (Bar mleczny) are a unique feature of Poland and you can find them wherever you go in the country. They are especially famous for tourists from Western countries wanting to have a "communist" experience.
Despite their names, they have nothing to do with milk but are cheap self-serviced restaurants. Back in the communist era the government subsidized them to provide affordable catering for workers, especially those who were working in places not big enough to have their own canteen. The name "milk bar" is coming from the fact that meat wasn't that common back then and so the menu consisted of mostly vegetarian meals.
Not anymore, now you can find everything.
Since these are the cheapest and most convenient places to have a quick lunch, locals still frequent them. As well as tourists, to have some sort glimpse how the old system worked.
There are several types of milk bars depending on how touristy the place is. But be prepared that everything will be in Polish and as they are self-serviced it will be a challenge to navigate them at first. Also, they will be full during lunchtime.
But if you want something quick, cheap, but proper, look for a milk bar. You'll find one nearby;
Poland's recent history is troubled, it had its share of the downsides of WWII and also the communism that came after that. And this is apparent wherever you go, many places show the destruction of the war, as well as how people tried to cope with the terrors afterwards. You'll see the PW (Kotwica, anchor) symbol in many places as this was used by the resistance against the occupation.
Also, the country got shifted to the west significantly. Wroclaw and Gdansk were German cities, while Lviv which is in Ukraine now was Polish. This creates interesting dynamics, like how people had to relocate and rebuild ruined cities they weren't sure they would still occupy in a few years.
The country has stringent laws against public alcohol consumption. Alcoholism is a problem widespread in Eastern Europe, and authorities are trying to do something about it. Because of this, if you drink alcohol in a public space you might be fined except for a few places. As an effect, there are a lot less drunken people on the streets.
Another uncommon thing is the 100 Zloty fine for jaywalking. I haven't seen anybody getting fined for crossing a red as a pedestrian, but I could feel that people are more likely to wait for the green before crossing than in other countries.
Bialowieza is all about the surrounding forest and the greenery. Long walks in the woods, small villages nearby, and of course, bisons.
Bialystok is the biggest city on the eastern side of Poland, and it's kind of a transport hub. There are trains connecting it to other parts of the country, and both the Bialowieza forest and Lithuania are easy to reach.
When people asked me which part of Poland is my favorite, I reply that it's Gdansk. It's a bustling place with every amenity you expect in a city yet so impregnated with history wherever you go you'll find something fascinating.
Krakow is a charming city conveniently located on the southern part of the country. In total, I've spent more than 2 weeks here.
Torun, a charming town mostly saved from the destruction of WWII, is located around halfway between Warsaw and Gdansk. If you travel on this route, make sure to stop by.
The capital of Poland, conveniently located and connected with all parts of the country.
I've heard that there are 3 places that are "must-visits" in Poland: Krakow, Wroclaw, and Gdansk. So after Krakow I took a bus and went to Wroclaw.