Boundaries were very fluid in the past, due to wars, conquest etc. The area that was East Prussia around Olstyn/Allenstein went into Poland in 1945. When I visited my ancestral area in NE Poland in 2000 (Suwalki Lomza), with my husband and brother, we had a look at some of the Prussian areas that went into Poland in 1945 in the vicinity of Elk (formerly Lyck) and Gizycko, and the scenery and style of buildings were completely different to the Polish areas over the former border, even now. And the same is true for roads and rail - they still stop and go N-S rather than E-W direction, due to now long-gone old borders.
However, the exception to this is Konigsberg itself. This became the Russian enclave of Kaliningrad. Konigsberg/Kaliningrad was the centre for the football world cup when it was held in Russia a few years ago.
Jill Whitehead, Surrey UK
jill.whitehead@...>