Kelsterbach is part of the Frankfurt Rhein-Main urban area. After World War II , many of the businesses in Kelsterbach were connected to Frankfurt Airport , which is located adjacent to the town. The sender notes that this card from Brussels was purchased during a weekend trip. The photo shows Parc du Cinquantenaire (Park of the Fiftieth Anniversary), a large urban park of about 30 hectares located in the eastern part of the European Quarter. The “fiftieth anniversary” refers to the Belgian Revolution , when the southern provinces of the Kingdom of the Netherlands seceded and established the Kingdom of Belgium. The centerpiece of the complex is the Cinquantenaire Arch , completed in 1905. The park is filled with gardens, ponds, and landscaped green spaces. Prior to 1930, it hosted numerous trade fairs, exhibitions, and festivals. Today, it serves primarily as a public leisure park. The northern part of the complex houses the Royal Museum of the Armed Forces and Military History ...

Neu-Isenburg is part of the Frankfurt Rhein-Main urban area and has a population of nearly 40 000 people. The town is home to Autokino Gravenbruch , the oldest drive-in movie theatre in Europe. Neu-Isenburg is also well known in the region for its annual Open Doors Festival (formerly known as Musikspektakel). Over three days, around 40 bands and artists from a wide range of musical genres perform. The free event attracts approximately 15 000 visitors and takes place across several stages throughout the town.