In the entire northern part of the Barcelonès county this is the only Romanesque building that has survived intact to our day. It is a tower with a circular floor plan and irregular walls made up of different sized stones and blocks, with a tendency to be smaller in size. The tower is crowned by battlements that have been restored in the modern period.
The tower is 19 metres high and 7.75 m in diameter, and is raised over top of an uneven foundation that stand out wider than the tower diameter. At the base the walls are 240 centimetres thick, though with each floor they become narrower on the inside, being scaled, so that by the upper floor the walls have come down to 140 centimetres thick.
Over time, doors and windows have been opened up in the tower.