Dien Bien Ohu
This example shows it pretty well http://sites.google.com/site/lrnthaccnt/home/vietnamese-accent
The Siege of Vicksburg was fought in the vicinity of Vicksburg, MS.
Acre Acre Acre
Vicksburg was the site of the siege, not a commander of the battle.
Try this site: http://en.wikipedia.org/wiki/Roman_siege_engines
Orléans, on the Loire river suffered a siege during the Hundred Years War.
They weren't normally moved. Armies would build them on site when they began a siege.
Dien Bien Phu, which was the site of a two-month siege and the fiercest battle after WWII. Link goes to a wikipedia article about the battle.
I would say it's around 50-70%, depending on the site.
Construction began on the present site in 1724.
Wichita city was under siege near the of the war
The proper adjective for "Vietnamese" is "Vietnamese." For example, "Vietnamese cuisine" or "Vietnamese culture."