So, I happened to run across this and since I had done a couple posts here on barrels, I just figured I’d post this here for fun.
This is the “Heidelberg tun” and is the fourth such enormous barrel to be created and placed in Heidelberg castle, dating back to the 16th century. Reportedly making this barrel (I guess a monstrous barrel is called a “tun”) required a couple dozen entire oak trees.
This one stores wine. There have been a couple of similar, although much smaller “tuns” that have stored beer.