Until the early 1970s the economy of Offenbach was mainly the machine-building and leather industries. The city is the home of the German Association for Electrical, Electronic and Information Technologies until today.
Offenbach has the following twin cities:
Heilbronn
Heibronn ( ]; Alemannic German: "Hailbrunn", local dialect: "Hallbrunn", "Haalbrunn") is a city in Germany in the state of Baden-Württemberg. With about 117,000 people, Heilbronn is the sixth largest town in Baden-Württemberg.
Heilbronn is also on the river Neckar and is known for the wine which was grown in their region and the Kätchen a famous sign.
Hildesheim
It has about 110,000 people living there.
Hildesheim is one of the oldest cities in North Germany. The city may have been founded when the bishop moved from Elze to the Innerste ford, where it was an important market on the Hellweg trade route. The settlement soon grew into a town which was granted market rights by King Otto III in 983. Originally the market was held on a street called Old Market ("Alter Markt"), which still exists today. The first market place was laid out around Saint Andrew's Church. As the city grew larger, a larger market place became more important. The current market place in Hildesheim was made at the start of the 13th century when the city had a population of about 5,000. When Hildesheim obtained city rights in 1249, it was one of the largest cities in Northern Germany. For four centuries the clergy ruled Hildesheim, before a city hall was built and the citizens gained some influence and independence. Construction of the present City Hall started in 1268, and in 1367 Hildesheim became a member of the Hanseatic League. A war between the citizens and their bishop cost dearly in 1519-1523 when they engaged in a feud. Hildesheim became Protestant in 1542, and only the cathedral and a few other buildings remained in Imperial (Roman Catholic) hands. Several villages around the city remained Roman Catholic as well. In 1813, after the Napoleonic Wars, the town became part of the Kingdom of Hanover, which was annexed by the Kingdom of Prussia after the Austro-Prussian War in 1866 as a province.
The city was bombed in World War II, but the bombing had little importance in the course of the war. 28.5% of the houses were destroyed and 44.7% damaged. 26.8% of the houses had no damage. The center, which still had its medieval character until then, was almost levelled. As in many cities, priority was given to rapid building of badly needed housing, and concrete structures took the place of the destroyed buildings. Fortunately, most of the major churches, two of them now UNESCO World Heritage Sites, were rebuilt in the original style soon after the war. During the war, valuable world heritage materials had been hidden in the basement of the city wall. In 1978, the University of Hildesheim was founded. In the 1980s a reconstruction of the historic center began. Some of the new concrete buildings near the marketplace were torn down. Replicas of the original buildings were built in their place.
¹ census data
Pforzheim
Pforzheim (Alemannic German: "Pforze") is a city in the German state of Baden-Württemberg.
It has about 116,000 inhabitants.
Recklinghausen
Recklinghausen (Westphalian: "Riäkelhusen") is a city in the German state of North Rhine-Westphalia, belonging to the Ruhr area. It has about 120,000 inhabitants.
Wolfsburg
Wolfsburg is a city in the German state of Lower Saxony.
It had about 124,000 inhabitants in 2016. The automobile company Volkswagen has its main office in Wolfsburg.
Bergisch Gladbach
Bergisch Gladbach (; Ripuarian: "Jläbbisch") is a city in the German state of North Rhine-Westphalia.
It is near to Cologne and has about 110,016 inhabitants.
Erlangen
Erlangen (; East Franconian: "Erlang") is a German city in the state of Bavaria.
It has about 105,000 inhabitants.
Erlangen is near to Nuremberg ("Nürnberg"). Both cities share the University Erlangen-Nürnberg.
Gera
Gera is a city in the east of Germany, in the state of Thuringia.
It has about 100,000 inhabitants.
In the beginning, "Gera" was not the name of a village or city, but of a region or district. This district was mentioned in a document for the first time in the year 995. Four years later, in 999, the Holy Roman Emperor Otto III gave this district to his sister Adelheid, who was an abbess in Quedlinburg.
In the center of this area, the "provincia Gera", a town with the same name was established. Another document, which is from the year 1237, said for the first time that there was a town called Gera. In this town, the abbesses of Quedlinburg had some officials which were called the "Vögte" of Gera. These officials were the ancestors of the counts and princes of Reuß, which reigned in Gera for many years, until the year 1918.
In the early modern period, Gera was famous for making textiles. There were some fires in which a lot of the town was destroyed, for example in 1686 and in 1780. In 1806, Napoleon was in Gera before the Battle of Jena.
In the 19th century, Gera became an important city of industry. Before that, Gera was a quite small town, but in the year 1900, it had already about 45,000 inhabitants.
In 1920, Thuringia was founded as a state of the Weimar Republic. Gera was the biggest city of the state, because Erfurt was not yet a part of Thuringia. At the end of World War II, some parts of Gera were destroyed by bombs, for example the Osterstein Castle.
After World War II, Gera was in the Soviet Occupation Zone and then in the German Democratic Republic (GDR). From 1952 to 1990, it was the capital of the Gera District ("Bezirk Gera") of the GDR.
Since the German Reunification in 1990, Gera belongs to the Free State of Thuringia in the Federal Republic of Germany.
Since 1959, Gera has had more than 100,000 inhabitants. The highest number of inhabitants of Gera was 134,834 in the year 1988. Since the German Reunification, the number of inhabitants becomes smaller and smaller. Now there are fewer people who live in Gera than in Jena, so Gera is only the third-biggest city in Thuringia. On 31 December 2008, there were only 100,643 people living in Gera.
Gera has got twelve twin towns. Eleven of them are in Europe.
These famous people were born in Gera:
Remscheid
Remscheid is a city in the German state of North Rhine-Westphalia.
It has about 115,000 inhabitants.
Undernet
Undernet is an Internet Relay Chat network that was made in 1992. It has many channels, but there are few limits to what kind of channels can be made.
Advanced Micro Devices
Advanced Micro Devices, Inc. (AMD) is a large American company from Sunnyvale, California that makes computer hardware. It makes many different computer parts, but it is most famous for its central processing units (CPUs). Another important product are motherboard chipsets. It started as a company that made products for Intel, another large hardware company. In 2006 they bought ATI Technologies.
Ryzen is AMD's brand name for their CPUs. Ryzen CPUs have between 2 and 32 cores and can achieve speeds above 4 Gigahertz (or GHz). Radeon is their brand name for other computer products like GPUs.
Illinois Institute of Technology
The Illinois Institute of Technology (IIT) is a private university in Chicago, Illinois, United States. It is one of the best universities in the United States as U.S. News & World Report, a magazine, puts it at number 108. Most students of this university focus on science or technology as their major, or subject they study most. IIT was created in 1940 by the merger of the Armour Institute of Technology and Lewis Institute.