This list is in alphabetical order, places are not ranked.
# 1
This is place is so unique, because it is one of the last and largest remaining parts of the huge primeval forest that many centuries ago was spreading across the European Plain.
Białowieża Forest is UNESCO World Heritage Site and Biosphere Reserve.
# 2
Fortifications in Hel - north of Poland at the Baltic Sea. Hel is the name of narrow peninsula, which is 300 m wide in the most narrow place close to Jurata.
Hel Peninsula was considered as one of the most important military areas and after 1918, when Poland gained independence, Polish army decided to build there a naval base. Today it is very popular place among tourists, especially windsurfers due to strong winds.
If you get there, you shouldn't miss to see some of the many bunkers, which it is possible to enter. I attach the link to a page with some picture, although it is in Polish, just scroll down and look at the pictures.
# 3
Góry Stołowe - The Stołowe Mountains, part of Middle Sudety Mountains,
Picture by hr.icio
Mountains structured from plated rocks, making overall amazing impression. This is the only mountains of its kind in Poland. Abundant in different kind of habitats - scientists counted 16 of them in total and claim it valuable for European nature.
#4
Krakow - city in the south of Poland.
You may know it as Cracow. Wonderful, old city that dates back to the 7th century. Starting from the Stone Age it has been grown to one of the most important cities in Poland.
There is an oldest and best in Poland Jagiellonian University with very old library containg large collection of medieval manuscripts.
# 5
Marienburg Castle in Malbork - north of Poland.
# 6
Picture by Pawel Bak
Nikiszowiec was build 100 years ago for coal mine workers. Place is very unique in entire Europe, also among film producers.
Peatbogs and marshes of Biebrza River - located in north-eastern Poland within Grajewo County.
Picture by Jurek Durczak
This is vast and untouched fenlands, where you can see unique plants, rare wetland birds and other animals (Elk or Beaver) and other. This is very important place of birds’ nesting, feeding and resting. From 1995 this place is under protection of the Ramsar Convention. The most unique part is under strict protection, if you want to see it look for Red Marsh.
# 8
Polish Jura Chain - (Jura Krakowsko-Częstochowska) part of Jurassic system in the south-central Poland.
Picture by Maciek Bor
This is a hilly landscape that consists of vast limestone formations, cliffs and about 220 caves. It is a part of Ojcow National Park - one of the most attractive in Poland.
#9
Toruń - city in northern Poland.
This is an extraordinary, beautiful medieval city and place where Nikolaus Copernicus was born - it is possible to visit a house from XV century, where he was born.
Warsaw Old Town - central Poland.
Picture by Jarosław Pocztarski
This oldest part of the city is definately worth to see. It was established in XIII century and still keeps the mood. There is many restaurants, cafes, shops etc.
Best buy befre you come to Poland - Michelin Poland (Michelin Map) (Multilingual Edition).