St. Peter's Cathedral
This is the most important and most magnificent Gothic building in Bavaria. It was begun around 1250, replacing a Romaneque church of which the "Eselsturm" is the only remaining part above ground. Don't miss the late 13th century statue of the Annunciation and the beautiful stained-glass windows (14th century) in the south transept. In the cloisters - accessible only on guided tours - you will see many Romanesque frescoes. Concerts are held regularly. If you can catch by any chance tickets for the "Domspatzen" (the "Cathedral Sparrows"), do it, they have some of the finest choristers in the country.
Address:
Tel:

Steinerne Brücke
Germany's oldest surviving stone bridge (built 1135-1146). From here you have the most beautiful view of the city's medieval skyline. At the time it was build this bridge was the only safe and fortified crossing along the entire length of the Danube.
Address:
Tel:

Reichstagsmuseum
The first German parliament building, seat of the "immerwährender Reichstag" ("everlasting Imperial Diet"). The most significant room is the Imperial Diet Chamber, a parliamentary forum for the empire from 1663 to 1806.
Address: in the Old Town Hall
Tel:

Email:
openings=tours Mon - Sat 3.15pm in English

Castle of the Princes of Thurn and Taxis
Former abbey, expanded in the 19th century to create the present Schloss complex, which is still inhabited and only open to the public partly. A guide will show you the state rooms, with some wonderful Brussels tapestiries on the wall.
Address:
Tel:

Email:
openings=tours Mon - Fri 11am - 4pm every two hours, Sat & Sun also 10am

Historical Museum
Art and cultural history, especially the Albrecht Altdorfer section shouldn't be missed.
Address: Dachauplatz
Tel:

Email:
openings=Tue - Sat 10am - 4pm

Kepler-Gedächtnishaus
Memorial to the astronomer Johannes Kepler, who died in Regensburg (original instruments and models).
Address: Keplerstrasse
Tel:

Email:
openings=Tue - Sun 10am - 4pm, tours available.