If you feel more energetic, you can take the Himmelsleiter (Heaven's Ladder or Sky Ladder) – a stairway of 1200 steps winding up 270 meters (890 ft) up to Königstuhl. It ends 10 meters east of the mountain top funicular station. The lower end of stairs is just above the castle, but a bit hidden.
© OpenStreetMap contributors
The castle is above the old town, south of the river, and can be reached by mountain railway (included in the ticket price) or staircase. An audio guide tour of the castle and its grounds is available for a fee near the entrance. It is available in several languages, including English. There is also a statue to the German poet Johann Wolfgang von Goethe in the castle gardens. The castle grounds are free to visit, and offer a great view of the city and river.
Hauptstraße is the main street, which leads from Bismarckplatz across the old town. Approximately 1.6 km in length, it is reputedly the longest pedestrian shopping street in Germany.
The Heiliggeistkirche (Church of the Holy Spirit) is only one of many large and small churches, but definitely the one with the most interesting history. During the Dark Ages, it was the shelter of the Bibliotheca Palatina, Germany's oldest library. The Bibliotheca was stolen and brought to Rome but eventually returned in pieces. Today, parts of it can be visited in the University Library (also the oldest and probably the most valuable of its kind in Germany), which is situated close to the old university. You can get a great view of the Heiliggeistkirche, Old Town, and the Neckar river bridge from the castle (Schloss Heidelberg).
It has 1712 Baroque construction with modern touches inside.
Old Bridge, Alte Brücke
Bridge constructed in 1788.
The old university in the old city.