St. Nikolai, Gothic church in Bad Sachsa, Germany.

St. Nikolai-Kirche is an Evangelical Lutheran church on a small hill in Bad Sachsa's historic centre. Its square tower, built of massive fieldstone, was probably a defensive tower in the 12th century; around 1300 it was joined to a small chapel by side walls to form the nave. The tower is topped by an eight-sided pointed spire with four dormers holding the clock faces, and a Prussian eagle serves as the weather vane.

The church tower originated in the 12th century as a defensive structure. A chapel was built around 1300 and subsequently connected to the tower to form the complete building that stands today.

The 1595 altar was donated by mayor Hartmann and built by an unknown artist in a cross-shaped form. Its triptych shows the Annunciation and Nativity on the side panels, the Last Supper in the centre, the Crucifixion above, and the Resurrection and Ascension at the top. The predella is made of stucco marble.

The church is entered through the doorway in the tower; inside, a round-arched passage leads from the tower hall into the nave, whose floor slopes down toward the altar to bridge the level between the tower and the former chapel. A half-timbered annex added on the south side in 1691 serves as the exit. The tower was clad in slate from autumn 2022 to summer 2023.

The black bird on the pulpit canopy is often mistaken for something else, but its curved beak, golden crown and the shield marked FR (Fridericus Rex) identify it as a Prussian eagle. It refers to Frederick III, crowned first King of Prussia in 1701, ten years before the pulpit was made.