Cornu Amoni (Nahum 3:9-12

This study was done using the Amplified Bible, which I don't have permission to publish, so I will replace the verses here with the American Standard Version.  Because of that some of the comments may not totally make sense because the AMP has expanded explanations.  I would highly recommend going to a site like BibleGateway.com where you can read the AMP version for free.

9 Ethiopia and Egypt were her strength, and it was infinite; Put and Lubim were thy helpers.

 A. No, as in No-Amon, is the original word, when used in conjunction with "Amon", it is a form of declaring the city of No as not only belonging to Amon, but literally in meaning to be "a portion of Amon".

B. Amon was the god of gods and the god of the wind.  He also held the position as being one of the rare gods who created himself.  This fact of the belief system of Thebes (No-Amon) gives us a glimpse at why Jehovah destroyed the city in such a definite fashion.  

Amon (Amun)

C.  The Greeks later on also began to worship Amon, however they mixed Amon with Zeus and created Ammon Zeus, a god they worshiped not as the original Zeus, but a form of him.  

Ammon Zeus -  Staatliche Antikensammlungen - Munich

D.  According to Wikipedia, "Several words derive from Amun via the Greek form, Ammon, such as ammonia and ammonite. The Romans called the ammonium chloride they collected from deposits near the Temple of Jupiter Amun in ancient Libya sal ammoniacus (salt of Amun) because of proximity to the nearby temple.[26] Ammonia, as well as being the chemical, is a genus name in the foraminifera. Both these foraminiferans (shelled Protozoa) and ammonites (extinct shelled cephalopods) bear spiral shells resembling a ram's, and Ammon's, horns. The regions of the hippocampus in the brain are called the cornu ammonis – literally "Amun's Horns", due to the horned appearance of the dark and light bands of cellular layers."

Ammonia beccarii, a benthic foram from the North Sea. - Wikipedia

Cornu Ammonis in the Hippocampus in the brain. - Brainmaps.org

10 Yet was she carried away, she went into captivity; her young children also were dashed in pieces at the head of all the streets; and they cast lots for her honorable men, and all her great men were bound in chains.

A.  The city of No was destroyed in a two-fold manner.  It was ironically Sennacherib, the evil one Nahum speaks about, who originally invaded and destroyed No (Thebes).  This, according to historians, took place about three years before he besieged Jerusalem.  Years after Sennacherib destroyed it, Nebuchadnezzar captured the city in the 500's and took its inhabitants into captivity.  In this case, Nahum is not only speaking about the first destruction, but actually prophesying of a second. 

11 Thou also shalt be drunken; thou shalt be hid; thou also shalt seek a stronghold because of the enemy.

A. Now Nahum returns to the subject of Nineveh.  The Ninevites shall be drunk not with wine or drink, but the wrath of God which is a far more potent force to consume.  This same fate that the powerful No-Amon faced, would now be imposed upon Nineveh.  The harlotry, or worship of others gods, depending on other forces for strength is what caused the destruction of these nations.

12 All thy fortresses shall be like fig-trees with the first-ripe figs: if they be shaken, they fall into the mouth of the eater.

A.  Ripe figs on the branch are very easily knocked to the ground.  Even with a healthy tree, the slightest shake can cause them to fall.  

B.  Ripe fruit is also desirable, just, as John Gill points out, would have been the fortresses of Nineveh to the invading armies.  They were of strategic strength and importance, and the Babylonians, Medes, Chaldeans, and others would have certainly desired to own them for the strength they provided.