The town's name of certain Latin origins derives from the names "Pellius" or "Oppilo", that with the addition of the suffix "-ica" (indicating ownership): probably was the name of the Roman to whom the lands were assigned.
Pianiga is a municipality in the province of Venice, situated in the extreme South-western corner of the province, in a flat area.
The area has been inhabited since prehistoric times, but the first stable settlement was founded by the Romans, who settled here between the II and III century A.D. They were able to coexist peacefully with local people, bringing development and wealth, thanks to the rational subdivision and land use, interventions to divert water courses and the construction of a dense network of roads to allow easy connections between the areas. To better control the borders and defend the territories a series of fortresses were built. Pianiga probably developed around one of these fortified places. The first official documents that report the existence of a centre, date back to the High Middle Ages, a time when the government of this land was assigned to several lords and monasteries. An important stage of the town's history is attributed to the domination by the Serenissima Republic of Venice, which lasted about 400 years, a period in which several noble and elegant residences were built.
- the Church of St. Martin of Tours, built in the early Middle Ages, in Romanesque style with Gothic details, has been repeatedly expanded and remodeled. The façade surmounted by a gable roof embellished by pinnacles and is preceded by a porch supported by two stone columns. The portal is surmounted by a lunette which contains a precious fresco. Inside are preserved the traces of a XVI century fresco, a XVII century chapel of the Baptistery and a XVII century altar on which stands a valuable wooden altarpiece. The mighty Bell Tower is located in a lateral position, with a belfry decorated with mullioned windows and surmounted by pinnacles. The tower is topped by a small dome surmounted by a spire;
- the Church dedicated to St. John the Baptist of Mellaredo, which features a classical façade with a tympanum supported by columns and beautiful mullioned windows above the porch. It is flanked by a Bell Tower with a square base, which features a belfry with a large arched openings and is topped by a spire.