Do you know of any modern pics that show this as true to form of years ago. Amazing facts! That would make it more tangible in the eyes of the apostles at the time. Thanks!
At the location today there is an artist's reconstruction of the site in ancient times. You can see them if you yahoo or google search images for Caesarea Philippi and the Gates of Hell.
An interesting side story is that the Greek era temples atop the rock were dedicated to Panis, the Greek god Pan who was the sudden fear, mischief and confusion (it is where we get the word panic). Pan is the Greek God of shepherds and flocks and depicted in mythology as being half man and half goat.
Also of interest is the fact that although the cave is filled with rock due to earthquake activity in Jesus' day it was full of water and no one had ever measured the depth. The deepest sounding line tried in ancient times put the depth of the water at over 800 ft. The ancients would throw their sacrifices in and believe the gods were answering positively if the blood was seen in the springs nearby which form the source of the Jordan River.