The castle is younger than it looks. Between 2007 and 2011, the Ukrainian doctor and public activist Olha Bohomolets transformed a derelict building on the water in the town of Radomyshl, in Zhytomyr Oblast, into a historical and cultural complex. At its heart is an old flour mill, raised in the late nineteenth century by a Polish engineer named Piekarski. But the ground beneath it runs far deeper into history. The mill stood upon the ruins of a paper mill built in 1612 on the order of Yelysei Pletenetskyi, the archimandrite of the great Kyiv-Pechersk Lavra, a churchman who helped launch early Ukrainian printing. During reconstruction, researchers discovered the building had once been intended to serve as a fortress. Since 2011 the castle has been part of the Council of Europe's Via Regia cultural route, meant to knit European countries together through tourism.

The castle's soul is its Museum of Ukrainian Home Icons, built on a private collection Bohomolets began gathering in 1996. It is perhaps the only museum of its kind anywhere. More than 5,000 icons and sculptures fill it, Orthodox, Catholic, and Greek-Catholic works created across Ukraine between the sixteenth and twentieth centuries, the kind of images that hung not in cathedrals but in ordinary homes, watching over families through generations. The oldest treasure is an icon of St. Nicholas carved in stone, believed to date from the twelfth century. Some pieces carry the marks of harder times, rescued from burning, scarred by the aggressive atheism of the Soviet decades. Together they form a portrait of everyday faith in Ukraine, painted over four centuries by anonymous hands.

Radomysl Castle is more than a gallery. Its interior blends the feel of the late medieval and early modern worlds, and its rooms are made to be used. A Ceremonial Hall hosts special occasions, weddings above all. A concert hall seating 150 has welcomed classical, chamber, folk, and jazz performances, including the celebrated Ukrainian folk singer Nina Matviyenko, and it holds a distinction almost certainly unique in Europe: its own natural water spring rises within the hall. The castle's refectory doubles as a small museum, its walls hung with fine copies of old maps from the fifteenth through nineteenth centuries, its great oven able to cook a meal or warm the room as a fireplace.

Around the castle stretches a landscape park designed to disturb nature as little as possible. Fresh springs bubble up here too, offering a cold drink to anyone who walks the grounds. Most of the trees and flowers are rare species, among them iris, pink and white lilies, English garden roses, magnolias, and the water caltrop Trapa rossica, listed in Ukraine's Red Book of endangered species. The park has become home to beavers, otters, minks, and water voles, wildlife thriving where machinery once ground grain. Sculptures of St. Michael from the seventeenth to nineteenth centuries watch over the paths, and near the site of the old paper mill stands a monument to Yelysei Pletenetskyi, unveiled in 2009, said to be the only monument in Ukraine set upon the surface of moving water.