Home to the oldest university in the country, the Heidelberg University, and one of the most underrated destinations to visit, Heidelberg is a gem hidden in the Rhine Neckar river valley. Known for its romantic energy, fantastic cityscapes, picturesque urban and rural setting and a baroque styled Altstadt (old town), the beautiful riverside city oozes a rich cultural past. The ruins of the Heidelberg Castle have stood strong for over 800 years and is a testament of the city's rich history. It is known to be the warmest city in Germany and a sunny day in Heidelberg is totally worth it.