The first mention of Dortmund was in 885, when it was called Throtmanni. It became a free imperial city in 1220 and shortly after that joined the Hanseatic League , a defensive confederation of merchant guilds and towns in Europe. It came into existence in the late twelfth century and grew in members and power until after the end of the Thirty Years' War. It was the chief city of the Rhine during the 13th and 14th centuries.
In 1320, the name of the city, was Dorpmunde, which was so prosperous, the King of England borrowed money from the merchant families of Dortmund.
In 1803, Dortmund became part of the Principality of Nassau-Orange-Fulda, resulting it the loss of the city's status as a free imperial city. In the fall of 1806, the French occupied the County of Dortmund and in 1808, it found itself part of the Grand Duchy of Berg. In 1815, the Grand Duchy of Berg, including Dortmund, was annexed to the Kingdom of Prussia. Meanwhile, the state mining of the Ruhr area was founded and moved to Dortmund. Dortmund was a district seat within Regierungsbezirk Arnsberg until 1875 when it was demoted, so to speak, to an urban district in the region.
While Prussia was undergoing industrialization, Dortmund became a major hub for coal and steel. The town grew into a city, with a population which grew from 57,742 in 1875 to 379,950 in 1905, and several new residential areas popped up within a decade.
There was massive upheaval in 1920, with resistance being the order of the day. A group of Germans, led byWolfgang Kapp and Walther von Luttwitz, were planning a coup of the Weimar Republic, overthrowing the government, undoing the changes made in the 1918-19 German Revolution. and replacing it with a right-wing, autocratic government. The name of this attempted coup was the Kapp Putsch, after its leaders, and it had plenty of support from such groups as the military, nationalists, and monarchist factions. But three days later, after a large portion of the German population joined a general strike, causing most of the civil servants to be noncooperative with Kapp, Luttwitz, and their group. Dortmund was the seat of the resistance to the Kapp-Putsch.
In 1933, during the early part of World War II, under Nazi Germany, the government forced the Jewish community in Dortmund to sell the Old Synagogue. The Nazis appropriated the money to finance the regime. The Old Synagogue had opened in 1900 and had 1,300 seats, making it one of the largest houses of worship in all of Germany. In 1938, that same government destroyed the house of worship.
Also during the war, beginning in 1939, Dortmund's Aplerbeck Hospital transferred physically and mentally disabled patients to the Haramar Mental Hospital in the state of Hesse. Inside the hospital was the Haadamar Euthanasia Centre, which was one of six sites the Nazis used for mass sterilizations as well as murder of "undesirables." It is thought that more than 200,000 people with disabilities were put to death there, including hundreds of children. In fact, 229 children from Dortmund were transferred there and presumably killed.
After the war, only a few of the old buildings in Dortmund were restored, though large parts of the city were rebuilt during the 1950s. In 1958, construction began o a new opera house on the site of the Old Synagogue. The opera house was finished in 1965. A memorial plaque stands in the forecourt.
 
 
Recommended Resources
The city of Dortmund presents information about what life is like in the city, its history, which stretches back more than 1,100 years, city government and the city council, and the city's efforts to be as environmentally friendly as possible. The site also delves into the details of its zoo and the Hoesch Museum which seeks to keep the memory of the steel industry alive to help people remember their heritage.
https://www.dortmund.de/en/index.html
Contains a quick history of Dortmund, its medieval church, the Dortumund Petrikirche or St. Petri Church, the Dortmund Westfalenpark which is a 75-hectare park. There is also a rather extensive article about the Dortmund Zoo Park, which has more than 1,800 animals and which specializes in South American animals after the 1975 birth of its first giant anteater. This website also has information about a bevy of pubs, nightclubs, and restaurants in town.
http://www.smart-travel-germany.com/dortmund.html
Lays out data about the hotel, with detailed descriptions of the rooms and amenities including free parking, free WiFi, and 24-hour room service. There is a section about how to get to the hotel and what is nearby with a map which augments the site's directions from various places, including the train, a car via the A40 or the A2, by taxi cab from Dortmund Central Station and by taxi from Dortmund Airport. Also, there is contact information such as phone number, email, and physical address.
http://www.hotel-ambiente.info/home.html?L=1