The Masku Church, built probably in 1490-1510, and surroundings represents one of the oldest parishes in Western Finland. The Masku parish was mentioned first time in 1234. The Mural paintings and pulpit date from the 17th century. There are also several medieval artefacts like crucifix and Silesian altarpiece located inside the church. Near the church is also "Humikkalan kalmisto", an Iron Age burial ground.
Finnish National Board of Antiquities has described the church area as national built heritage.
The church of the former Franciscan monastery was built probably between 1515 and 1520. It is located in the UNESCO World Heritage Site of Old Rauma. The church stands by the small stream of Raumanjoki (Rauma river).
The exact age of the Church of the Holy Cross is unknown, but it was built to serve as the monastery church of the Rauma Franciscan Friary. The monastery had been established in the early 15th century and a wooden church was built on this location around the year 1420.
The Church of the Holy Cross served the monastery until 1538, when it was abandoned for a hundred years as the Franciscan friary was disbanded in the Swedish Reformation. The church was re-established as a Lutheran church in 1640, when the nearby Church of the Holy Trinity was destroyed by fire.
The choir of the two-aisle grey granite church features medieval murals and frescoes. The white steeple of the church was built in 1816 and has served as a landmark for seafarers.