Rambling up the southern side of the Heiligenberg, across the Neckar from the castle, one will find the Philosopher's Walk. Its name, it is said, stems from the fact that university professors and philosophers walked there, perhaps using the solitude of the forest and the incredible views of the city and surrounding area for inspiration. The philosophers' trail is about two kilometers long. Although the beginning of the path is marked, it is not easy to find. Initially, the steep and winding road runs for the first 700 meters through one of the most expensive districts in Heidelberg. Then comes to the Philosophers' Garden, with a beautiful view of the city. If you visit Heidelberg during the summer months, you will notice an interesting feature about the Philosopher's Walk – it has a climate which is much more temperate, almost Mediterranean-like, than that of the valley. In fact, you will see many plants growing here that normally cannot thrive in the northern, more milder weather, such as lemon trees, pomegranates, cypresses, and palm trees.
One of the first places you can see this exotic vegetation is the Philosopher’s Garden. This has several flower beds and some benches as well, which allow visitors to sit, relax, and enjoy the view. Also in the garden is a memorial stone to Joseph von Eichendorff, a romantic poet who studied in Heidelberg from 1807-8.