Ahenny

You can find these high crosses at Ahenny, and they date back to the eighth and ninth centuries. I'm going to briefly explain the gist- but first let me say there are students/ scholars who earn their masters and PhD's studying these crosses and everything about them- so my explanation is just that- a gist...
The early Christians who built these crosses were on a mission to Christianize the world, and at the time, (there wasn't, to their knowledge, a North or South America), Ireland was the farthest point from the center (the center being Jerusalem, where Jesus was crucified), so as far as they were concerned, the mission was completed and the world would end very soon!
The stone crosses have elaborate detail, one could only imagine how long it took to complete this. The center, which I just explained, is why the horizontal part of the cross is lower than traditional crosses we see, to symbolize the center, and that He is at the center of everything, the center is where everything begins and ends. The omphalos (navel, center point) is there to symbolize how important the Crucifixion is for salvation history.
The crosses have Bible stories carved in them, and start at the bottom and go up, as whoever was praying would be on his knees.