Heidelberg's Old Town Marktplaz (Altstadt) is full of cafes, restaurants, and pubs with the Gothic Heiliggeistkirche (Church of the Holy Spirit) in the center of the square. This university town is also known for its Studentenkarzer, a student jail that was used to troublesome students from 1778 to 1914.
The Old Bridge of Heidelberg is an iconic pedestrian bridge that offers scenic views of the Old Town and the Neckar River. Be sure to visit Neckarweise Park along the east bank and enjoy a relaxing stroll along the river.
The Heidelberg Castle is a 16th-century red sandstone castle on the hillside overlooking Heidelberg Altstadt. The castle ruins are one of the most important Renaissance structures north of the Alps. The earliest structure was built in 1214 but was later expanded into two castles around 1294.
This castle is unique because it has been struck by lightning twice, once in 1537 and again in 1764. Both times the castle was damaged and needed to be repaired, however, after the second strike, much of the stone was taken from the south wall to build the Schwetzingen Castle.