Château de Saint-Béat dates from the 12th century. It was enlarged by Henri IV (1553 – 1610). Rulers rarely lived in Saint-Béat; the castle was occupied by captains until the 16th century. In 1588, the Parlement of Toulouse passed a law that required the inhabitants of Melles, Argut and Arlos by turns to guard the castle, subject to a fine of 500 écus. The castle never had to repel invasions, though its strategic position close to the Spanish border led to it being described as 'la clef de France' (the key to France).
The castle was surrounded by two enceintes. The keep measures 5m square and had two storeys. The castle provides views over the village and the Garonne valley.
References:The first written record of church in Danmark locality date back to the year 1291. Close to the church are several stones with a Christian text and cross inscribed. The oldest parts of the present red-brick church are from the 1300s. In the late 1400s the church was enlarged to the appearance it has today. The church has been modified both internally and externally several times, among other things after the fires in 1699 and 1889. There are lot of well-preserved mural paintings in the walls.