This semi-postal issue from Luxembourg’s 1964 Caritas series features a vivid modernist painting titled Les Trois Tours (“The Three Towers”). The design depicts stylized castle towers set against a pink and red sky, with bold contrasting blocks of color—green, crimson, and black—reflecting the mid-20th-century artistic movement that celebrated abstraction and emotion. The 50c + 10c denomination indicates that 10 centimes from each sale supported charitable causes through Caritas Luxembourg. Printed by Courvoisier S.A., this stamp exemplifies Luxembourg’s tradition of combining fine art with social purpose.