Laubach Castle. Laubach is a town of approximately 10,000 people in the Gießen region of Hessen, Germany. Laubach is known as a Luftkurort, a climatic clean air health resort. The main point of attraction is the castle belonging to the Count Solms-Laubach family. The castle was built in the thirteenth century and expanded over the years. The Solms castle has one of the largest private libraries in Europe, with over 120,000 titles.