Complex sentence: The green area that comprises the municipality of Midden-Delfland was named Midden-Delfland before 2004, and it referred to the green area surrounded by cities (you can see the centres of The Hague and Rotterdam) and the horticulture area of Westland.
Split into simpler sentences: The green area that comprises the municipality of Midden-Delfland was called Midden-Delfland before 2004. It referred to the green area surrounded by cities (you can see the centres of The Hague and Rotterdam) and the horticulture area of Westland.