Sites.

This is coolbert: 

Twenty!

Yet  still additionally a list as obtained from "The Reader's Companion to Military History";

"The Best Western Military Sites"

As compiled by Robert Crowley: "We have listed here the twenty military sites that we consider . . . 'worth a visit'. We use the word site: not all are battlefields. We have also limited our choices to the West, recognizing that we are omitting what might be the greatest military site in the world, The Great Wall of China."

* Meggido.  [Israel]

* Masada. [Israel]

* Hadrian's Wall.  [England]

* Cadbury Castle.  [England]

* Aigues-Mortes.  [France]

* Lutzen.  [Germany]

* Neuf-Breisach.  [France]

* Louisbourg.  [Canada]

* Saratoga.  [USA]

* West Point.  [USA]

* Valmy.  [France]

* Austerlitz.  [Czech Republic]

* Antietam.  [USA]

* Gettysburg.  [USA]

* Vicksburg.  [USA]

* Verdun.  [France]

* The Somme.  [France]

* The Maginot Line at Hackenberg.  [France]

* The Churchill War Room.  [England]

* The D-Day Beaches.  [France]

Go here and see an outstanding virtual 360 degree tour of the Maginot Line at Hackenberg.

Additionally to the list and cannot be ignored worthy of inclusion in my opinion

* Tunnels of Củ Chi. [Vietnam].
* Carcassonne.  [France]
* Krak of the Chevaliers. [Syria]

coolbert.