The neoclassical "Cisternino" of Pian di Rota is also known as "Purgatory in Pian di Rota" for its function of filter and collector of waters. Completed in 1851 on a project by Pasquale Poccianti and sited in the lush countryside, the building is quadrilateral in shape and has two semicircular apses on the sides. The facade is lightened by a portico surmounted by a pediment. Two inscriptions in Latin on the facade recall that the work was begun under Grand Duke Ferdinando III of Lorraine and terminated under his successor Leopold II. In 1852 it was filled with water from the springs of Colognole. Continuing along the canalizations over the arches, the water reached the "Cisternone" of Livorno.