The spectacular Ypres in Flanders.

Especially when you learn that no recognisable buildings were left at all, following the cessation of hostilities in 1918.  Ypres is also famous for the Menin Gate (see extra) that contains the names of over 54,000 souls whose bodies were never found. 
Wouldn't you have thought that we stupid people would have learned some lessons? Yet here we are again with those two ego-maniacal madmen from North Korea and the USA.