Solvay Castle, 19th century castle in La Hulpe, Belgium.

Solvay Castle is a 19th-century mansion built in the Flemish Neo-Renaissance style in La Hulpe, Belgium, with symmetrically arranged gardens and ornamental sculptures on the grounds. The building sits at the heart of a large estate that includes ponds, woodlands, and several outbuildings scattered across the property.

The manor house was completed in the 1840s for the Marquis Maximilien de Béthune on the outskirts of Brussels. In 1893 the industrialist Ernest Solvay bought the estate, remodeled the castle from its Flemish neo-Renaissance look and laid out a French formal garden. The property was given to the Regional Government of Wallonia in 1968 on condition that it serve educational purposes.

The Folon Foundation occupies the old farmhouse on the estate and displays the work of Belgian artist Jean-Michel Folon. Visitors can see his colorful watercolors, sculptures, and posters in rooms that were originally used for farming.

The grounds are free to enter and three marked walking trails guide visitors through the woods, ponds, and open fields. Those with mobility difficulties will find wide, level paths throughout much of the estate.

A 36-meter (about 118 feet) tall obelisk topped with a golden sun marks the edge of the property and can be seen through a straight clearing cut through the forest. This line of sight was deliberately designed to draw the eye from the mansion toward the monument.