Preservation of battlefields

Ran across something about a Wal-Mart and a battlefield today:

Preservation issues -- such as the one going on with Wal-Mart and the Wilderness battlefield -- are going to become only more contentious in coming years as suburban sprawl and economic development collide with once-rural Civil War battlefields.

It often comes down to a matter of money vs. history.

It got me thinking about how battlefields might just be beginning to be encroached in America but with Korea having less than 3% of the total land mass of America, this problem has surely been addressed time after time in Korea's population dense nation, right? What is the future of the Korean War's Iron Triangle or the Punch Bowl? The field where the Battle of Gapyong seems to be doing fine but when will that change? Hell, the whole DMZ for that matter... These are just within the last sixty years, though. I can't imagine old Koguryo-era battlefields and what they look like today. Curiously, I can't seem to find any land battle markers that predate the Korean War. Obviously hundreds exist but my internet search skills seem to be failing me at the moment. Any help from the peanut gallery? Any Japanese invasion fields I should know about? 삼국시대 battlefields?

I suppose the obvious answer has always been to bulldoze and build over any significant piece of land regardless of its past save for a few that have gone incidentally untouched. It is nice to find a particularly old timey gate being restored in its original location.