Pollença’s most emblematic monument is the Castell del Rei, one of the island’s three rock fortresses in the Valley of Ternelles, approximately 492 meters high. It is catalogued as a Heritage of Cultural Interest and was named after King Jaume I.

In Roman times, it was already used as a fortification, and during the Muslim period it was (along with the Castle of Alaró) the last stronghold of resistance from the troops of Jaume I of Aragon, who invaded Mallorca in 1229. They resisted until March 1231.

Another prominent historical fact related to the castle was the resistance offered in 1343, and during a three-month siege, by the last of those faithful to the king of Mallorca Jaume III, after he lost his kingdom and had annexed to the Crown of Aragon.

The castle was used as a watchtower rather than grounds for defence. It was abandoned in the 18th century and is currently in ruins, of private ownership and closed to the public. Currently the road leading to the castle has been reason for controversy. Although it is a public road, the owners (the March family) have managed to restrict access.

The poet Miquel Costa i Llobera wrote the poem Castillo del Rey in 1896, "U castell d'u rei" in the Pollençan dialect.