A country plagued by suffering and endemic violence in the 20th century has only recently redeveloped and reenergised itself into a modern , well-connected and influential republic. Its tragic history is well documented in Warsaw, whose museums and monuments recount the horrors of the Nazi occupation as well as the protest movements and resistance which liberated the country from communist rule. The capital is also a present day architectural and cultural marvel, with lively nightlife and elegant streets and open spaces. Auschwitz-Birkenau is the world's most sombre museum. The largest and most meticulously planned of the WWII concentration camps bore witness to the deaths of over one million people over a four-year period. The nearby city of Krakow retains much of its medieval layout with a huge, 800 year old central market square stood for 800 years and some several magnificent and imposing churches. Gdansk is the baltic coast's most beautifully restored settlement with a particularly colourful facade that revitalises a city ravaged by war. Tatra National Park is a natural paradise filled with undulating green hills and mountains as well as lakes, waterfalls and caves.