Better watch it sharksfan...if the "Lernt Deutschland kennen!" bug bites you, you can kiss a few paychecks goodbye!
For those who aren't familiar with the series:
The "Lernt Deutschland kennen" (Get to Know Germany) cards were issued over a span of 30+ years. Each card featured a scenic German picture on the left side. Any German town could order the cards and choose the view, provided they ordered at least 50,000 cards. I can't speak for the total number of varieties over the 30+ year span, but during the period I collect (up to 1945), there were about 2,700 different cards.
Michel catalogs these in major varieties, with most major varieties then subdivided into the individual printing sets.
Sharksfan, your cards all appear to be Michel P305, which were printed in 1941-42. There are a total of 378 different varieties of P305 (14 sets of 27). I see portions of at least two printing sets in your photos -- sets 42-8-1- and 42-9-1-, both of which consisted of 27 cards each.
These are lovely cards (yours are in great shape!), and they're one of my favorite collecting areas. The cards themselves are generally inexpensive, it's just the sheer quantity that gets you. I have a stack of about 1,000 of these that I bought in bulk waiting for me to wade through, scan, post to my collection, etc. If I come across any duplicates I'll let you know.