bigthink.com/strange-maps/hunger-stones-europe/
As rivers run dry in central Europe, they reveal a type of low-water mark particular to that part of the world, the so-called Hungersteine, or “hunger stones.” These rocks are only visible when water levels are extremely low. Over centuries, they have been interpreted as warning signs of imminent crop failures and even famine, and they were inscribed with dates or sayings marking the event.
Being a history junkie it's fascinating to think of a society and culture that had the foresight, and energy to devise these stark alerts to unborn generations. It's a testament to their faith(s). It's also a very good comparator to how in these days we clearly aren't giving a flying fuck about future generations.
Oh, look ! A squirrel !