In 1815, Hamburg joined the German Confederation as a Free and Hanseatic City, but stayed away from the German Customs Union for the time being. The Rauhe Haus was built in Hamburg-Horn in 1833 by J. H. Wichern founded. Hamburg adopted a new constitution in 1860. Two years after the German War (1866), in which Hamburg had not actively participated, military sovereignty was transferred to Prussia. Hamburg remained customs abroad, which became untenable after the transition of the Reich to the protective tariff policy (1879). With the agreements concluded in 1881 and implemented in 1888, the entire residential city of Hamburg joined the German customs association, while a free area was created for the port. Until the First World War, this regulation led to constant improvements in the port and electricity construction facilities and made Hamburg both a sea gate and one of the most important industrial locations in Germany. Accordingly, the population rose from (1880) 412,000 to (1900) 706,000 by 1913 to 1,030,000. See ABBREVIATIONFINDER.ORG for acronyms about Hamburg.
In 1921 Hamburg received a parliamentary-democratic constitution; The first mayors were: Arnold Friedrich Georg Diestel (1920–24), C. Petersen (1924–29, 1932–33), Rudolf Ross (1930–31). In 1933 the National Socialist Reich government dissolved the elected citizenship and placed the city under a Reich governor (K. Kaufmann). In 1937 the Prussian cities of Altona, Wandsbek, Harburg-Wilhelmsburg and 27 rural communities were incorporated; Cuxhaven came to the province of Hanover, Geesthacht to Schleswig-Holstein. Large-scale air raids (especially March 4th and between July 24th and 30th 1943, April 8th / 9th 1945) caused severe destruction (around 55,000 deaths).
On May 3, 1945, Hamburg became part of the British occupation zone without a fight. As a result of dismantling, the city lost a substantial part of the shipbuilding industry and, as a result of the forced transfer of ownership to the victorious powers, most of the merchant ships (including fishing vessels) based in it. In 1948 the economy began to be rebuilt (shipbuilding, establishment of a shipping-independent industry, merchant shipping). During the German split (1949–90), the city lost an important part of its economic hinterland.
In 1949 the city became a Land of the Federal Republic of Germany. On June 6, 1952, the “Constitution of the Free and Hanseatic City of Hamburg” came into force. The strongest party in Hamburg from the first general election in November 1946 to September 2001 was always the SPD (1946–53, 1957–74, 1978–82 and 1982–86 absolute majority), from the CDU only from June to December 1982 and from November Ousted from this position from 1986 to May 1987; Until 2001 the SPD – except 1953–57 Kurt Sieveking (* 1897, † 1986; CDU) – provided the First Mayor: 1946–53 and 1957–60 M. Brauer, 1961–65 Paul Nevermann (* 1902, † 1979), 1965–71 Herbert Weichmann (* 1896, † 1983), 1971–74 Peter Schulz (* 1930, † 2013), 1974–81 Hans-Ulrich Klose (* 1937), 1981–88 K. von Dohnanyi, 1988–97 H. Voscherau from 1993 in cooperation with the voter association, instead of party, established in the same year, 1997–2001 Ortwin Runde (* 1944; for the first time in one Coalition with the Green Alternative List (GAL; until 2012 name for the Hamburg regional association of Bündnis 90 / Die Grünen). From 2001, O. von Beust (CDU) was first mayor, initially in a “civic block” government made up of the CDU, FDP and the temporarily strong “Schill Party” (named after its founder), with an absolute majority of mandates from 2004, with the GAL from 2008. O. von Beust resigned from his office in August 2010, and was succeeded by C. Ahlhaus (CDU). On November 28, 2010, the GAL prematurely ended its coalition with the CDU. In the general election on February 20, 2011, the SPD won an absolute majority of the seats. O. Scholz (SPD) was elected First Mayor on March 7, 2011. The SPD, led by O. Scholz, also won the 2015 general election by a clear margin, but lost an absolute majority. SPD and Alliance 90 / The Greens agreed on a coalition government. O. Scholz was re-elected First Mayor on April 15, 2015. In a referendum on November 29, 2015, a majority of 51.6% rejected the city’s application for the 2024 Olympic Games. A G20 summit took place in Hamburg on July 7th and 8th, 2017. In this context, there was devastation, arson and looting by militant G20 opponents. Severe clashes between the security forces and the perpetrators left hundreds of people injured. At the end of March 13, 2018, O. Scholz resigned from the office of First Mayor and became Minister of Finance in the new federal government of A. Merkelon March 14, 2018 . On March 28, 2018, P. Tschentscher (SPD) was elected as the new First Mayor.
From the 12th century onwards, the city of Hamburg was repeatedly plagued by devastating storm surges (evidenced by the so-called Julian flood of 1164 with great damage to the first Elbe dykes and the “Große Manntränke” [“Grote Mandränke”] from 1362, one of the largest storm surges and Natural disasters in the Middle Ages, especially in North Frisia). The storm surge triggered by a hurricane over the North Sea in the night of February 16 to 17, 1962 shook with its 60 dike breaches, the inclusion of the population of Neuenfelde and Altenwerder as well as floods that lasted for days (up to 150 km 2; Highest water level in Sankt Pauli 5.70 m; 315 fatalities in the area of the city) the security consciousness of the Hamburg citizens and led to the establishment of a committee of inquiry; the rescue measures were directed by Interior Senator H. Schmidt. As a result of the protective measures and dyke reinforcements initiated in its wake, the next storm surge (January 3 and 21, 1976) – despite the highest water level in Sankt Pauli of 6.45 m – remained largely without consequences.