.

 

Defensive Earthworks  

 "Now behold, the Lamanites could not get into their forts of security by any other way save by the entrance, because of the highness of the bank which had been thrown up, and the depth of the ditch which had been dug round about, save it were by the entrance.
And thus, were the Nephites prepared to destroy all such as should attempt to climb up to enter the fort by any other way....Thus they were prepared... to smite down all who should attempt to come into their place of security by the place of entrance...."  (Alma 49:18-20) 72 BC

"And we began... to repair the walls of the city, yea, even the walls of the city of Lehi-Nephi...."  (Mosiah 9:8)

"And they were prepared that they could cast stones from the top thereof... and slay him who should attempt to approach near the walls of the city... Thus, Moroni did prepare strongholds... round about every city in all the land." (Alma 50:5-6)

"...many who heard the words of Samuel, the Lamanite, which he spake upon the walls of the city."  (Helaman 16:1). about 6 BC

----------------------

  Becan Defensive Earthworks  

 Becán means "ravine or canyon formed by water" in Maya, and refers to the moat that surrounds the city. Becán, however, is not an old or authentic place name, but was conferred on the site in 1934 by archaeologists of the Third Campeche Expedition. This expedition reached the site on February 20, 1934 to investigate reports received the previous month.  
Becán was at the peak of its development around A.D. 800, shortly after the cessation of major construction. Most of the buildings shown were built centuries earlier.

(David L. Webster Implications for Maya Warfare (Tulane University, Middle American Research Institute, Publication 41, 1976), p. 108)
 ---------------------- 

Tikal  Defensive Earthworks  
"Sprawling Maya network Discovered under Guatemala Jungles"
"Researchers have found more than 60,000 hidden Maya ruins in Guatemala in a major archaeological breakthrough.
    << Tikal Guatemala
  "Laser technology was used to survey digitally beneath the forest canopy, revealing houses, palaces, elevated highways, and defensive fortifications."

 (Sprawing Maya network discovered under Guatemala Jungles, BBC News, Feb, 2, 2018) 
------------------
Additional Information

Tikal, an ancient city in northern Guatemala.  "The Tikal earth works were discovered...The trench is the most prominent feature of the earthworks...."

Defensive EarthWorks at Tikal (by Dennis E. Pulston & Donald W. Callender, Jr., Expedition Spring 1967 Page 40-48)

 Digging into the Book of Mormon:   Our Changing Understanding of Ancient America and Its Scripture  (Sept. 1984 Ensign, by John L. Sorenson)

---------------------
A Comparative Study of Fortification Developments Throughout The Maya Region and Implications of Warfare, (by Marisol Cortes Rincon, B.A.: M.A.)