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Konstanz is situated on Lake Constance (the Bodensee in German). The Rhine river, which starts in the Swiss Alps, passes through Lake Constance and leaves it again, considerably larger, by flowing under a bridge connecting the two parts of the city. North of the river lies the larger part of the city with residential areas, industrial estates, and the University of Konstanz; while south of the river is the old town which houses the administrative centre and shopping facilities in addition to the Hochschule or the University of Applied Sciences. Car ferries provide access across Lake Constance to Meersburg, and the Katamaran provides a shuttle service for pedestrians to Friedrichshafen. To the south, the old town borders onto the Swiss town of Kreuzlingen.
The first traces of civilization in Konstanz date back to the late Stone Age. Around 50 AD, the first Romans settled on the site. Its name, originally Constantia, comes from the Roman emperor Constantius Chlorus who fought the Alemanni in the region and fortified the town around 300 AD.
Around 585 the first bishop took residence in Konstanz and marked the beginning of the city's importance as a spiritual center. By the late Middle Ages, about one fourth of Konstanz's 5,000 inhabitants were exempt from taxation on account of clerical rights.
Trade thrived during the Middle Ages; Konstanz owned the only bridge in the region which crossed the Rhine, making it a strategic place. Their linen production had made an international name and the city was prosperous. In 1192, Konstanz gained the status of Imperial City so it was henceforth subject only to the Holy Roman Emperor.
In 1414–1418 the Council of Constance took place, during which, on 6 July 1415, Jan Hus (Czech religious thinker, philosopher and reformer), who was seen as a threat to Christianity by the Roman Catholic Church, was burned at the stake. It was here that the Papal Schism was ended and Pope Martin V was elected during the only conclave ever held north of the Alps. Ulrich von Richental's illustrated chronicle of the Council of Constance testifies to all the major happenings during the Council, as well as showing the everyday life of medieval Konstanz. The Konzilgebäude where the conclave was held can still be seen standing by the harbour. Close by stands the Imperia, a statue that was erected in 1993 to remind of the Council.
In 1460 the Swiss Confederacy conquered Thurgau, Konstanz's natural hinterland. Konstanz then made an attempt to get admitted to the Swiss Confederacy, but the forest cantons voted against its entry, fearing over-bearing city states; Konstanz then entered the Swabian League instead. In the Swabian War of 1499, Konstanz lost its last privileges over Thurgau to the Confederation.
The Protestant Reformation took hold in Konstanz in the 1520s, headed by Ambrosius Blarer. Soon the city declared itself officially Protestant, pictures were removed from the churches, and the bishop temporarily moved to Meersburg, a small town across the lake. The city first followed the Tetrapolitan Confession, and then the Augsburg Confession. However, in 1548 Emperor Charles V imposed the Imperial Ban on Konstanz and it had to surrender to Habsburg Austria which had immediately attacked. Thus, Konstanz lost its status as imperial city. The new Habsburg rulers were eager to re-Catholicise the town and in 1604 a Jesuit College was opened. Its accompanying theater, built in 1610, is the oldest theater in Germany still performing regularly.
The city became part of the Grand Duchy of Baden in 1806. In 1821, the Bishopric of Constance was dissolved and became part of the Archdiocese of Freiburg. Konstanz became part of the German Empire in 1871 during the unification of Germany. After World War I it was included within the Republic of Baden.
Because it practically lies within Switzerland, directly adjacent to the Swiss border, Konstanz was not bombed by the Allied Forces during World War II. The city left all its lights on at night, and thus fooled the bombers into thinking it was actually Switzerland. After the war, Konstanz was included first in South Baden and then in the new state of Baden-Württemberg.
The Altstadt (Old Town), which is large considering the small size of modern Konstanz, has many old buildings and twisted alleys. The city scene is marked by the majestic "Münster" Cathedral ("Münster Unserer Lieben Frau"), several other churches and three towers left over from the city wall, one of which marks the place of the former medieval bridge over the Rhine.
The University of Konstanz was established close to the town in 1966. It houses an excellent library with approximately two million books, all freely accessible 24 hours a day.
Konstanz is served by major railway lines running west to Singen with connections to all parts of Germany, and south into Switzerland, connecting to major routes at Weinfelden. Services are provided by the Deutsche Bahn AG and also the Swiss Thurbo company and its German subsidiary. The nearest airport is at Friedrichshafen, which can be reached by a fast ferry service on the lake, which also connects Konstanz to other lakeside towns. The airport mainly hosts domestic flights, but a service to London Stansted Airport is available. The nearest international airports are in Stuttgart, in Basel, and Zurich, which has a direct train from Konstanz. Bus services within the city are provided by SüdbadenBus GmbH.
Additionally Konstanz and Friedrichshafen have been connected by the two (and soon three) catamarans Constance and Fridolin since 2005.