Kasteel Bel-Air is an 18th-century castle in Willebroek, Belgium, built around 1810 in late classicist style and distinguished by a portico with Doric columns. The municipality purchased the estate in 1974, and the castle opened as a cultural center in 1975, hosting meetings, lectures, educational activities, exhibitions, and small concerts. The surrounding green park was renovated and reopened in 2018, providing a scenic setting for this elegant historic residence.