The Otto Henry Building: Frederick II was succeeded in 1556 by Otto Henry. Although he was only to rule for three years, he must be accounted one of the most important Prince Electors. He led his people to the new doctrines of the Reformation and commissioned the artistically most significant palace of the castle, the Otto Henry Building. Its harmoniously designed and richly decorated facade facing the castle courtyard is regarded as the most magnificient example of German Renaissance secular architecture.
The principal figures in the niches between the windows are all of the same height, even though the height of each story is different. It represents a magnificient first flowering of the Renaissance style in the city, whose influence can be seen in the lovely facade of the Knight's House by the Church of the Holy Spirit.

Town Hall (Rathaus): The predecessor of the present day town hall was destroyed by French troops in 1689. The foundation-stone for Heidelberg's new town hall was laid in 1701 and work began. Due to a fire, the town hall had to be reconstructed in 1908. Several houses located south of the building along the 'Hauptstrasse' were pulled down and replaced by the new building which was to become part of the town hall. The east building of the town hall had been built before, in 1886. Another building including a small bell tower was added here in 1961. It replaced the 'Gasthaus zum Großen Faß' which had been located here from 1720 to 1956, a historic restaurant with the shape of the Castle‘s 'Big Barrel'.

Convention Center (Stadthalle): Apart from Heidelberg Castle and Old Bridge, Heidelberg's City Convention Hall located on the banks of the Neckar river is the most distinctive landmark of the Old Town district. Built in a late historicist style, it is an internationally renowned location for successfull congresses and festivals. Its 100th birthday was officially celebrated in October 2003 with a variety of events.
The building was designed by the Heidelberg architects Jakob Henkenhaf and Friedrich Ebert and was completed in 1903. The architectural style, following the tradition of the „German Renaissance”, is also to be found at the Friedrich Building of the Heidelberg Castle. The south facade facing the „Untere Neckarstrasse” depicts portraits of university professors and famous artists.

The Madonna at the Kornmarkt: On the way to the castle, only a few steps away from the Marktplatz you find the Kornmarkt (grain market). This is the oldest square in Heidelberg. From here one has a fine view up to the magnificient castle ruins.
In its centre is the statue of Virgin Mary. The market square was erected in 16th century on the foundation of an old hospital. It was used as market for milk and herbage, later also for grains. That's where the name derives from.
In 1685, the Palatinate, to this date a protestant region, was taken over by a Catholic sovereign. He did everything to "convince" his subjects to return to Catholic beliefs started a religious propaganda campaign. Jesuits supported this campaign erected Madonna statues wherever they could - one of which is the "Madonna of the Kornmarkt". The Madonna was erected by a Catholic fraternity. When the sovereign offically declared Mary the patron saint of the Catholic belief in the Kurpfalz, the statue became a focal point of religious worship in Heidelberg. The Madonna of the Kornmarkt demonstrates three typical characteristics of this period: Mary is shown as the Queen of Heaven, as a virgin and as a victor.

Old Bridge: The four preceding bridges were wooden constructions. Again and again they were destroyed by floods, fire and ice. Prince Elector Karl Theodor was the first ruler to have construct a stone bridge which was erected here from 1786 to 1788. Well preserved is the medieval bridge gate on the town side, originally part of the town wall. Baroque tower helmets were added during the erection of the stone bridge in 1788. Also located here is a plaque referring to the defence of Heidelberg against French troops.
On October 16, 1798, a brave Austrian regiment commanded by Prince Schwarzenberg succeeded in repulsing the advancing French Army. The West Tower contains dungeons, whereas the East Tower holds a spiral staircase. A few steps of it visitors will find the „Tränktor” (Drinking Gate). During the Middle Ages, cattle were driven through this gate to their drinking places. The two bays of the bridge carry monuments created by Franz Konrad Linck (1730 - 1793) who, since 1763, was the Prince Elector's official court sculpturist.