The tower of Cala Piccola, also known as Cala Piatti tower, is a coastal tower located in the municipality of Monte Argentario. Its location is at the western coastal stretch of the Argentario promontory, within the area of a hotel residence.
The tower was built by the Sienese during the Renaissance, more precisely during the fifteenth century, as a reference point for the defensive system of the southern coastal stretch of the Republic of Siena. The current coastal fortification was rebuilt by the Spaniards in the second half of the sixteenth century, to enhance it and make it more functional in carrying out functions of sighting and active and passive defense within the coastal defense system of the State of the Presidios.
The tower continued to perform its original functions for many centuries, even during the nineteenth century, when it became part of the Grand Duchy of Tuscany; after the unification of Italy it was decided to divest it and sold to private individuals in 1867.
In the last century the fortification was incorporated in the area of the current hotel residence.
The tower of Cala Piccola has a circular plan, with a mighty base with a cordoned shoe which, on the whole, presents itself as an imposing truncated conical structure, on which the upper part of the turriform structure rests, spread over three levels.
The external walls appeared to be covered in stone and sometimes with dull plaster, with some loopholes and small square windows that open at different heights; the access door to the tower opens on the mezzanine floor where it is reached through a characteristic flight of external stairs that is articulated on the part facing the ground.
The upper part is without crowns, with the summit terrace that was originally used by the sentinels for the sighting functions.