Convent of Christ.
The castle and monastery at Tomar was originally built by the Knights Templar in the 12th Century. When the Templars were abolished in the early 14th Century, the pragmatic King Dinis of Portugal created a new order, the knights of Christ and the property and members in Portugal transferred to that.
The order lost its military role and the castle was abandoned but the monestry flourished. It's very extensive and contains an amazing rotunda, full of lavish carving and bright colours.
A short distance west of Tomar is the Pegões Aqueduct.