The Castle of Muñatones in Muskiz is one of Bizkaia's most outstanding fortresses, and was built in the mid 15th century by the chronicler Lópe García de Salazar.
Like the majority of Basque mediaeval castles, this castle spreads outwards from a central nucleus, from a completely impenetrable cubic fort-tower with battlements, and surrounded by a rectangular walled area with a cube in each corner and square towers on two of its sides that serve as entrances. Through this approach we penetrate the second line of defence, also fortified and leading to the tower itself, whose structure is a strong vertical cube with a square layout. The tower, inner ward and some of the cubes form the outer embrasure. Over the main access, in the second ward, the coats of arms of the Muñatones, Salazar and Butrón families may be seen.
The tower is one of the buildings that have seen most fights between warring factions. The insecurity of the times made it wise to include a moat, today half levelled out, and also led to the need for a drawbridge, these being fairly unusual defence mechanisms in the fortified towers of Bizkaia.
Also in Muskiz we find the 15th century
Pobal Foundry, currently undergoing alteration work in order to make it into a museum.