Before World War 2 most of today's northern Poland was ethnically and politically German.
During the 13th-15th centuries pagan Lithuania fought a seeminly eternal war against the German Teutonic Knights who sought to spread Christianity (according to critics, more likely to loot and destroy). Their headquarters was Malbork (Marienburg) castle, today rebuilt for better imagination of knights' lifestyle.
The largest of the battles against the crusading knights took place in Grunewald (known as Tannenberg in Germany, Žalgiris in Lithuania). ~70 000 soldiers participated in this one of the largest medieval battles where a united Lithuanian and Polish force vanquished the Teutonic Knights. The battlefield is now a popular tourist place with medieval souvenirs and a megalomanic monument. The battle has a great importance in Lithuania as many streets and sports franchises are named after it, including the most powerful basketball (Žalgiris Kaunas) and football (Žalgiris Vilnius) teams.
In Soldin forest near Myslibisz a plane "Lituanica" crashed in 1933. Piloted by Steponas Darius and Stasys Girėnas this plane flew succesfully over the Atlantic with destination in Kaunas only several hundred kilometers away. It was the second longest flight time today, first Lithuanian plane to cross the Atlantic and the world's first transatlantic air mail service (the mail did not burn and was symbollicaly flown from the crash site to Lithuania the next day). The pilots became martyrs and even the Nazi Germany permitted construction of the Lithuanian pilots monument (two interlinked crosses) at the crash site in 1936 despite the German claim over Klaipėda region which shattered Lithuanian hopes to particiapte in Berlin olympic games the same year. The monument has original German and Lithuanian plaques. After World War 2 when the lands were added to communist Poland a Polish plaque was installed. Curiously the monument surivived even the iconoclastic communist regime and remained a place of respect. A traditional Lithuanian chapel-post now stands at the place where Steponas Darius body was discovered; a memorial barn is nearby.