The towers of Kurtuvenai St. Apostle Jacob's Church have been leaning against the sky since 1792 when the 10-year construction of the sanctuary was completed. The towers of the snowy church in the late Baroque style are 50 meters high and visible from far away. There is the coat of arms of the church founder Count Jokubas Nagurskis family above the main entrance of the building. The interior of the church savours of classical moderation although you can discover the late baroque and neo-gothic aesthetic elements. The ensemble of five altars and a pulpit was completed in 1820. The event is marked by a memorial plaque mounted on a pillar of the church.
The main altar is the most pronounced highlight of the church. A professional painting Saint Jacob in carved gilded frames is hanging in the middle of the altar. Sculptures of the four evangelists with symbolic attributes are situated on both sides of the picture between the columns: Matthew with an angel, Mark with a lion, John with an eagle and Luke with a bull. The sculptures were created in the 19th century. Boxes for the estate owner's family were set up in a bay on the right side of the main altar.
The wooden pulpit is decorated with a figure of an angel with a table of the Ten Commandments and a figure of a pigeon representing the Holy Spirit. The two side altars alongside the base are of the same structure, except that the left altar was decorated with neo-gothic wood carvings in 1873. Our Lady of Grace statue and the picture of Saint Joseph are placed in the left altar. By 1873 there was the painting The Blessed Virgin Mary the Paraclete of Prisoners in the statue's place. It should be associated with the feast of the Blessed Virgin Mary of Prisoners which is held in Kurtuvenai parish. An icon hanging next to the altar is said to have been donated by the Tsarist Russian soldiers who were digging the Windawski Canal near Kurtuvenai (1825-1831). Sacred Heart of Jesus statue is in the lower slot of the right altar while a carved sculpture of the crucified Christ is in the upper slot. A statuette of the Infant Jesus King of Heaven (The Infant of Prague) next to it is surrounded by abundant tokens of gratitude donated by the congregation. The pictures of St. Anthony and St. Mary Magdalene are hanging in the right altar in the middle of the church. The picture of St. Anthony was brought here from the old church of Kurtuvenai. The altar on the left is decorated with the paintings of St. Isidore and St. George. Both paintings were created around 1821.
The organ founded by Jokubas Nagurskis is one of the oldest works of art in the church. It is believed that it was built by organ builder Nicolaus Friedrich Jantzen around 1796 and reconstructed by Otto Kratokvil in 1932-1933. The oldest part of the installation - the organ prospectus - has survived. It is made of wood in the late Baroque style decorated with gilded carvings. The prospectus center is decorated with the sculpture of King David playing the Harp and the apices are crowned with angels blowing the trumpets.
Despite the spaciousness of the church, it has plenty mysterious dark corners and narrow corridors. The mortuary cellars are shrouded in greatest secrecy. Two of the counts Plater Zyberk family representatives were laid to their eternal rest in the family vault under the sacristy. The great cellar (120 sq. m.) is installed in front of the main altar. There are 12 crypts under magnificent brick vaults. People were buried here in the late 18th - the early 19th century. The church founder J. Nagurskis is believed to have been buried in the central crypt located directly under the main altar. Mysterious stories have been woven around mummified remains contained in another crypt.