In the 15th century, Zrinski built his courtyard in center of the settlement of Brod Na Kupi. It was a three-story building on a square ground floor, and an outer fortress that is now in ruins. Kaštel Zrinski in Brod Na Kupi dates back to 1651. It was built by Prince Petar Zrinski , probably at the site of the old Zrinski family castle after 1577. In the courtyard behind the castle, which used to be the center of the Zrinski settlement, is the parish church of Sv. Marija Magdalena, which in 1670 was built in baroque style by Petar Zrinski . It was renovated in the 18th century. Today, Brod Na Kupi is home to the River Kupa Valley, aka the Valley of Butterflies. It is home to over 500 species of butterflies, and houses over 60% of Croatia’s butterfly fauna.