Money from the past

Today after running errands and gardening few hours (we finally had warm day, +14c and dry, mostly sunny) I made a google journey into the world of old money.

You see there was a small box of coins and old bills in my deceased dad's belongings.

This was one of the oldest bills there was. A one mark bill from probably 1918. Not sure yet, but after a couple of hours Googling I guess there was nothing too expensive there.

Susanna