You can't miss Stephansdom - the cathedral - right in the middle of the city. It is a Gothic building with an amazing roof covered with green, yellow, white and black tiles in geometric designs. There is a bronze model of the church outside the building - this gives you a feeling for the overall shape of the building and the roof design.
We climbed up the South Tower - 343 steps twist round and round. It cost us 8 Euros for a family ticket to endure this ordeal. At the top though you get a lovely panorama of the city and a great view of the amazing roof tiles. The climb back down is almost as bad - round and round again but this time your knees take all the strain. We all felt a bit dizzy at the bottom, but soon recovered!
Walk around the church and compare the height of the North and South Tower. The North Tower is very short compared to the soaring South Tower.
At the top of the North Tower is the Pummerin Bell. This is one of the biggest bells in Europe. It was completed in 1711 to commemorate the victory of Vienna against the invading Turks. In World War I the bell was destroyed, but was recast again afterwards from metal from the old bell.
Near the lift to the Pummerin is a sculpture of Jesus that originally stood outside the church. According to legend, three young men mocked the statue, attributing the suffering in Jesus' face to toothache. That night the three lads had terrible toothaches, until they returned to the church to ask forgiveness and their toothaches were cured.
Right next to this statue is a self portrait of Anton Pilgram, the stone mason who carved the pulpit in the middle of the church. e is leaning out over the sill, holding his compass and square.
The founder of the Hapsburg dynasty - Rudolph IV built the cathedral and he and his wife are buried in the crypt. In later years, the crypt became too crowded for all the Hapsburgs.
On Stephansplatz near the North Tower of Stephandsom, thre are lots of horse drawn carriages or fiaker lined up. I thoroughly recommend a ride in one of these - it is a delightful clip clop through the old streets. It cost us 65 Euro for 35 minutes, with the driver giving a commentary and pointing out places of interest.
There are lots of buskers and street performers also in Stephansplatz. Some of them are very good and we enjoyed watching them for an hour, while getting a much needed rest from pounding the pavements.
In the Middle Ages, Stephansplatz was occupied by a cemetery, but today is a popular meeting place for tourists and locals. If you go down to the entrance of the U1 and U3 subway lines under the square, you will see the remains of the 13th century Gothic chapel - Virgilkapelle. This chapel was uncovered during the construction of the underground tunnels.
On the corner of Stephansplatz and Karntnerstrasse look out for Stock im Eisen, a piece of wood covered in nails and enclosed in a protective case. The wood is said to be a leftover from the Viennese woods that once used to stretch as far as Stephansdom. 16th century blacksmiths used to drive a nail for luck into the tree, each time they left Vienna. Today, the gnarled and rusty log is covered with an almost uninterrupted casing of hand forged nails.
At noon every day in the Hoher Markt, watch twelve figures progress around the large guilded and copper Anker clock. Each figure is someone important from the history of Vienna, such as the Roman Marcus Aurelius, Empress Maria Theresia and Joseph Haydn.
Stroll along Kartnerstrasse and browse in the lovely shops there. Look out for Philharmonikerstrasse and on one side of this street, you will see the lights of Vienna's best known hotel - the Hotel Sacher. The Sachertorte is supposed to be delicious - we did not have time to try it unfortunately.
Eventually you come to the Staatsoper - the Opera House. It was built between 1861 and 1865 in a style inspired by the French Renaissance and faithfully reconstructed after World War II. It was so severely criticised when it was unveiled, that one of its architects, Eduard van der Null committed suicide.
You can see all these sights on foot and all in one day. There are also very good guided tours of Vienna - we did one of these on an extremely wet day, and as well as being very interesting and informative, they are a great way to get your bearings in this city full of architectural and historical treats.