Convento de Cristo, Portugal
The Convent of Christ in Tomar was originally a Templar stronghold built around 1160 as part of the defense system created to secure the border of the Christian Kingdom against the Moors. It was chosen as the headquarters of the Templar Knights in Portugal later in the 12th century and resisted the attacks of caliph Abu Yusuf al-Mansur in 1190.
The famous round church, or rotunda, was designed to resemble similar round structures in Jerusalem: the Church of the Holy Sepulchre and the Dome of the Rock, which was mistakenly believed to be part of the Temple of Solomon.
After the Order of the Knights Templar was dissolved in the 14th century, the Portuguese branch of the order was turned into the Knights of the Order of Christ and Tomar became its headquarters.