A historic site
If you go to Jerash to see the Roman ruins, you cannot miss the castle of Ajlun. It is very close to Jerash and the truth is that it is totally worth it.
The most surprising thing, beyond its strategic location high on a hill in the most fertile of all of Jordan, is how well-preserved it is and, above all, how well-kept it is, and above all, how clean and luminous it is inside. It's a place in which to spend an hour or so scouring nooks and walking among ruins, lit passageways, and admiring the views.