Set  on  the  top of the  highest mountain in the north of
Jordan is the impressive Arab Castle, Qal’at Al Rabadh,
which  was  built  in  1184/85  by Usama Ibn Munqith; a
nephew of Salah Eddin.  And was enlarged in 1214-15.
The castle resisted  the assaults of the Crusaders until
it fell to the  Mongols in 1260.  It was later rebuilt by the
Mamluks.
The castle  commands a view of the Jordan valley and
is a fine example of Islamic military architecture, which
used the tunnels, stairways and chambers.

The scenic Kings’ Highway  is a historic  road stretching from
Amman  to  Aqaba  along  5.000  years  and  littered  with the remains of Crusaders forts and outposts. The most important among  these  are  Karak  and  Shobak .  During  the Ottoman 
period  other  castles  and  caravanserais  were  built as rest stations on the pilgrimage route.The Crusaders built the Karak Castle in  1142 AD  with  the purpose of controlling the roads between Damascus and Egypt.  It was also used as a prison. The castle  itself  is more  imposing  than beautiful. It is a dark maze  of  stone - vaulted  halls and  endless passageways - though  it  is all  the  more  impressive  as  an  example of the Crusaders  architectural  military  genius. The  Shobak Castle
was built by Baldwin l in 1115 as an important Crusaders fort. The castle’s exterior is impressive, with a forbidding gate and encircling walls  three  layers  thick .  In 1185 it became under authority of Saladdin’s army. Re-used and remodeled during the Ayyubid, Mamluke and Ottoman periods.
Qal’at Al Tafileh is a small square tower, which is believed  to have been built the Ottomans for the main purpose of protecting the pilgrims. The lower  part  of its walls  includes huge stones  from prior ancient ruins.

As  if  the wonders  of  nature  are  not  enough,  Jordan’s  deserts  are dotted  with  ancient  castles, framing estates, forts, hunting  lodges and caravanserais widely varied in function, architectural style and  creative  embellishment.  Most were  the domain of Umayyad  Caliphs in the late 7th and early 8th centuries AD.

- Qasr Amra
  The most impressive  of the desert castles , is an early 8th century
  baths complex in a triple - vaulted  building full of  painted frescoes.

- Qasr Kharranah 
  Once thought to be built for defenses, is perhaps a former caravan-
  serai , where camel caravans pulled in for a few days rest on their 
  way.

- Qasr Mushatta
  Most  interesting  for  its use of  fired  bricks, its huge vaulted roofs
  and  its  23  semi-circular  towers.  It was such an ambitious under-
  taking that it was never completed.

- Qasr Al Hallabat
  The most ruined of  Umayyad  desert  complexes. It  was first used 
  as a 2nd century AD Roman fort that  was rebuilt in the reign of the
  Emperor Caracalla in the early 3rd century AD. Its Umayyad patrons
  turned  it  into  a  finely  decorated  building  full  of mosaics, carved 
  stucco,  woodwork  and  frescoes.  The nearby Hammam Al Sarah 
  baths is a smaller version of Qasr Amra.

- Qasr Azraq
  Located in the  middle of the Azraq oasis , was  Originally built as a
  Nabatean or Roman fort which was rebuilt in its present form in the
  early 13th century AD by Izzeddin Aybak; The Mamluke governor of
  the area. The Azraq area,  the only permanent  freshwater pools in
  the  surrounding  12.000  square miles  of  desert ,  is  an important 
  resting place for birds during the migration season