WWII monument...

WWII monument...  This is in the Netherlands, and they made it by taking a slice right out of the center of a Nazi bunker.  This site has lots more details, and a video of how they did it.

My US Navy and business travels took me to a lot of places in the world.  I spent quite a bit of time in eastern Europe, and also in southeast Asia.  One constant, virtually everywhere I went, was the presence of abandoned WWII construction.  Most of these leftovers weren't so much monuments as they were expensive and inconvenient to remove – so they just stayed there.  In the Philippines, Thailand, Russia, Estonia, Latvia, Finland, Australia, and Slovenia I ran across these derelicts as I traveled through the countryside.  In Estonia, in the '90s and '00s, I actually sought some of them out.  In some cases friends told me about them.  In other cases, books I'd read about WWII told me the locations, and I'd find them with my GPS and the aid of locals.  On Saaremaa (an island in the Baltic Sea that's part of Estonia), I've spent several days exploring WWII fortifications used by both sides to defend the Gulf of Riga.  In Russia, I spent a day exploring the area where the Nazis built a huge gun emplacement to attack St. Petersburg (then Leningrad).  In the Philippines, I spent two days on Corregidor Island, exploring its huge fortifications where the American defenders surrendered to Japanese attackers.  All of this brought home to me just how lucky America has been in the absence of combat on its shores – this sort of war memorial is almost non-existent on our territory (with the USS Arizona monument being a glaring exception).

However, there's another factor at work, too.  Some countries have actively removed most traces of WWII.  This includes America – we built huge numbers of shore defense bunkers and fortifications, as well as submarine and aircraft watch towers (many of reinforced concrete), and virtually all of these have been demolished.  In the U.K., there was even more such construction – and very little of it remains today.  France, Germany, and Italy have removed much of their WWII fortifications, though some has been carefully preserved.  In Estonia, one might stumble upon some WWII remnant anywhere you travel, sometimes in the most unexpected places.  So to some extent, the preservation of the WWII constructions seems to be a function of culture, or perhaps a country's wealth...