Remember the Alamo Walls

As a Vietnam Vet I know that physical barriers  can limit the number of uninvited "guests"   Even a barrier as relatively flimsy as concertina wire can discourage unwelcome  visitors.

The Texas Revolution demonstrates the potential benefits of walls.    The Battle of the Alamo was an epic defensive battle with Texas army co-commanders James Bowie and William B. Travis.
attempting to hold the walled Alamo mission they were using as a fort against  a vastly superior Mexican army under the command of  President General Antonio López de Santa Anna
 
Marty Robbins celebrated the defender's efforts in "the Ballad of the Alamo".

"One hundred and eighty five
Holdin' back five thousand
Five days, six days, eight days, ten
Travis held and held again."  

The Alamo's   walls helped Travis hold the fort until Gen. Santa Anna  decided to accept the high casualties needed to take the fort.  :Later at the Battle of San Jacinto Texas Gen. Sam Houston easily defeated Santa Anna because Santa Anna didn't have walls to protect his men.

The post office I was assigned to in Vietnam was initially located at a small compound south of Phu Cat AFB called Camp Fidel.  Even though the enemy wasn't likely to attack us instead of the Air /Force's jets, our commanders knew we had to guard our perimeter all night because the enemy wouldn't pass up an easy target.