Near the market square, on a magnificent hill, there is the collegiate church of st. Michael the Archangel.
The church was erected as the first in the area of today's Ostrowiec in 1614, thanks to the efforts of Janusz Ostrogski. There was a parish here and a hospital for the poor. The area around was used as a cemetery.
The temple was not spared the destruction caused by the seventeenth-century wars with Sweden. However, it was quickly rebuilt and consecrated in the 1970s. A significant expansion that gave the final shape to the body of the temple took place in the interwar period. The central nave was raised and lengthened, side aisles were added and the tower, which is the most characteristic element of the church, was erected.
When visiting the interior, pay attention to the beautiful grille, which was made in the local Ostrowiec Works. The church is a place where the memory of the tragic events of World War II is alive - you will find here many commemorative plaques dedicated to fallen soldiers, insurgents and ordinary inhabitants of Ostrowiec. The church is known as the "collegiate church", but it gained this rank relatively recently, only in 2000. In 1918, the church hosted Achilles Ratti, who celebrated a mass here as a papal inspector. A year later, this figure was known all over the world as Pius XI.