Frankfurt is home to several world-class museums, making it a perfect destination for art and history enthusiasts. Spend your rainy afternoon exploring the Städel Museum, which houses an impressive collection of European art spanning from the Middle Ages to the present day. Alternatively, you can visit the Senckenberg Natural History Museum, where you can discover fascinating exhibits on dinosaurs, fossils, and the natural world. Both museums offer a captivating indoor experience that will keep you entertained and enlightened on a rainy day.