Varel sits about 15 kilometers south of Wilhelmshaven and 30 kilometers north of Oldenburg, perched on the Geest - the slightly higher, sandier ground that German geographers distinguish from the wet marshes below. For centuries the town hugged this dry shelf while the lowlands stayed dangerous, prone to flooding from a North Sea that has redrawn this coast more than once. Then came the dykes. As earthworks pushed the water back, Varel crept downhill into ground that had once belonged to the tides. Today three-quarters of the municipality is farmland, and a surprising tenth is forest - unusually wooded for a coast where most towns face out across treeless polder. Walk to the western edge of the district at Dangast, and the land simply gives up. Mudflats stretch toward the horizon, and at low tide you can walk out onto them, the Wadden Sea's strange shining floor.

Charlotte Sophie of Aldenburg was born in 1715 and inherited Varel as her own ruling territory - a small dot of female sovereignty in a Europe that mostly did not allow such things. She corresponded with Voltaire, the sharpest pen of the French Enlightenment, and with Frederick II of Prussia, whose army would soon redraw the map of central Europe. What they made of this Frisian countess on the edge of nowhere is part of the puzzle: she was clearly something more than a curiosity to them, a woman whose mind could meet theirs across the long lag of 18th-century post. Her castle stood until the 19th century, when fire gutted most of it and the rest was pulled down. Only one building survives from the complex, and it happens to be the most extraordinary thing in Varel.

The castle church is the oldest building in town. Its first stones were laid in 1144; the tower went up between 1200 and 1250 as twin spires, rebuilt into its present shape in 1651 and reshaped again in 1737. But the reason art historians come to Varel is not the architecture - it is what stands inside. Between 1613 and 1618, the woodcarver Ludwig Munstermann carved the altar, font, and pulpit, and his altar climbs nearly ten meters into the church's gloom. It is one of the great surviving works of Northern German Mannerism, a style that took the calm of the Renaissance and twisted it into something restless and elongated, all writhing figures and exaggerated gestures. Before the Reformation, the church was dedicated to Saint Peter. Today it is plain Lutheran, no patron saint, and Munstermann's altar dominates the space like a frozen forest of saints and angels reaching for a heaven the Reformation no longer quite believed in.

For a town this size, Varel keeps producing people who outgrew it. Johann Gerhard Oncken, born here in 1800, would found the German and continental European Baptist churches - a quiet Frisian whose theology rippled across a continent. Lothar Meyer was born in 1830 and would later arrange the chemical elements into a periodic table independently of Dmitri Mendeleev, an achievement usually credited solely to the Russian; Mendeleev published his table in 1869; Meyer published his comprehensive version in 1870, within months of each other. His younger brother Oskar Emil Meyer became a physicist who studied the viscosity of gases. The dramatic soprano Hildegard Behrens was born in Varel in 1937 and grew up to sing Brunnhilde at the Met. More recently the footballer Deniz Undav, born here in 1996, has become a fixture in the German national team. Something about this damp corner of Friesland keeps sending people out into the world.

Varel is twinned with Jackson, Michigan, an industrial American town a continent and an ocean away. It is the kind of pairing that town twinning produces - improbable, slightly absurd, and somehow durable. From the air, Varel reveals itself as a compact cluster of red roofs ringed by patchwork fields, the green of forest pressing in from the south and the wide silver of the Jade Bight to the north. Twenty-one named localities make up the municipality, with names that read like a Frisian poem: Altjuhrden, Borgstede, Dangast, Obenstrohe, Streek. Somewhere down there, Munstermann's altar is still climbing toward its dark ceiling, and Charlotte Sophie's letters are still in archives, waiting for the next reader to be surprised that a small town on a muddy bay once spoke directly to the Enlightenment.