Some time ago I was posting the series of photos from old military fortifications of Karosta, Latvia with some nice small houses moving into the sea due natural sea/sand erosion.
Actually the fortification system at this part of Baltic Sea coast was much more developed and just few kilometers to the north there is another part of it called "The Northern Forts"

Full story here: https://steemit.com/mypictureday/@axeman/mypictureday-28-submission-the-wheels-of-blood