Oslo

===1900–present===
In 1948, Oslo merged with [[Aker, Norway|Aker]], a municipality which surrounded the capital and which was 27 times larger, thus creating the modern, vastly enlarged Oslo municipality. At the time, Aker was a mostly affluent, green suburban community, and the merger was unpopular in Aker.<ref>{{cite web |url=https://www.dagsavisen.no/oslo/kommunen-som-ble-slukt-av-oslo-1.1080868 |title=Da Høyre kjempet mot kommunesammenslåing |website=www.dagsavisen.no |date=8 January 2018 |access-date=4 January 2020 |archive-date=4 January 2020 |archive-url=https://web.archive.org/web/20200104012534/https://www.dagsavisen.no/oslo/kommunen-som-ble-slukt-av-oslo-1.1080868 |url-status=live}}</ref>

The municipality developed new areas such as [[Ullevål Hageby|Ullevål garden city]] (1918–1926) and [[Torshov]] (1917–1925). [[Oslo City Hall|City Hall]] was constructed in the former slum area of [[Vika, Oslo|Vika]] from 1931 to 1950. The municipality of [[Aker, Norway|Aker]] was incorporated into Oslo in 1948, and suburbs were developed, such as [[Lambertseter]] (from 1951). [[Aker Brygge]] was constructed on the site of the former [[shipyard]] [[Aker ASA|Akers Mekaniske Verksted]], from 1982 to 1998.

The original name of Oslo [[Geographical renaming|was restored]] in 1925.<ref>{{cite web |url=http://www.byarkivet.oslo.kommune.no/OBA/tobias/tobiasartikler/tob2001-1_01.htm |title=Oslo kommune byarkivet (Oslo City Archives) |publisher=Oslo Kommune |author=Bård Alsvik |access-date=23 September 2013 |archive-date=4 March 2012 |archive-url=https://web.archive.org/web/20120304212803/http://www.byarkivet.oslo.kommune.no/OBA/tobias/tobiasartikler/tob2001-1_01.htm |url-status=live}}</ref>

The city and municipality used the name ''Kristiania'' until 1 January 1925 when the name changed to ''Oslo''. Oslo was the name of an eastern suburb – it had been the site of the city centre, until the devastating 1624 fire. King [[Christian IV of Denmark]] ordered a new city built with his own name; Oslo remained a poor suburb outside the city border. In the early-20th century, Norwegians argued that a name memorialising a Danish king was inappropriate as the name of the capital of Norway, which became fully independent in 1905.<ref>{{Cite news |url=https://www.nrk.no/ostlandssendingen/xl/da-oslo-ble-oslo-1.13150638 |title=Da Oslo ble Oslo |last=NRK |work=NRK |access-date=5 May 2018 |language=nb-NO |archive-date=23 March 2017 |archive-url=https://web.archive.org/web/20170323202849/https://www.nrk.no/ostlandssendingen/xl/da-oslo-ble-oslo-1.13150638 |url-status=live}}</ref>

Norway was [[Operation Weserübung|invaded by Germany]] on 9 April 1940. Efforts to stop the invasion, most notably the [[Battle of Drøbak Sound|sinking of Blücher]], delayed the occupation of Oslo for a few hours which allowed [[Haakon VII of Norway|King Haakon]] to escape the city. Oslo remained occupied throughout the war until Germany capitulated in 1945. During this time, the occupying troops were harried by saboteurs in acts of resistance. On 31 December 1944, allied bombers missed their intended target and hit a tram, resulting in 79 civilian deaths.<ref>[https://www.aftenposten.no/oslo/i/w00o/hele-familien-ble-drept-av-britiske-bomber-paa-nyttaarsaften-anne-lise-juuls-far-erik-18-overlevde Hele familien ble drept av britiske bomber på nyttårsaften. Anne-Lise Juuls far Erik (18) overlevde.]</ref>

During the [[2011 Norway attacks]], Oslo was hit by a bomb blast that ripped through the [[Regjeringskvartalet|Government Quarter]], damaging several buildings including the building that houses the [[Office of the Prime Minister (Norway)|Office of the Prime Minister]]. Eight people died in the bomb attack.

On 25 June 2022, two people were killed and 21 others injured in [[2022 Oslo shooting|a mass shooting]]. An Iranian-born Norwegian citizen was subsequently charged with "aggravated terrorism".<ref name="BBC News-2022">{{Cite news |date=25 June 2022 |title=Oslo shooting: Norway attack being treated as Islamist terrorism, police say |language=en-GB |work=BBC News |url=https://www.bbc.com/news/world-europe-61933817 |access-date=25 June 2022 |archive-date=25 June 2022 |archive-url=https://web.archive.org/web/20220625164715/https://www.bbc.com/news/world-europe-61933817 |url-status=live }}</ref><ref>{{Cite news |date=10 November 2023 |first=Jan|last=Olsen|title=Iranian-born Norwegian man is charged over deadly Oslo Pride attack in 2022 |language=en-GB |work=Associated Press |url=https://apnews.com/article/norway-terror-radical-islamist-oslo-pride-attack-21cf3dcb4fcad4c24e2e5d0ec7c640ff |access-date=22 February 2024}}</ref>

The city has continued to expand. For a few years, new large scale housing areas and infrastructure projects are being built and planned across the city, notably in [[Hasle]],<ref>{{Cite web |last=Årdal |first=Tore |date=2021-10-01 |title=Haslelinje - Gigantutbyggingen gjennomført i løpet av ti år |url=https://www.estatenyheter.no/magasin/haslelinje---gigantutbyggingen-gjennomfort-i-lopet-av-ti-ar/309716 |access-date=2024-04-06 |website=www.estatenyheter.no |language=nb-NO}}</ref> [[Helsfyr]], <ref>{{Cite web |date=2023-11-15 |title=Store planer for områdene: Dette bygges på Bryn og Helsfyr nå |url=https://eiendomswatch.no/nyheter/kontor/article16601529.ece |access-date=2024-04-06 |website=eiendomswatch.no}}</ref>[[Bjørvika]],<ref>{{Cite web |date=2017-02-13 |title=Bjørvika - Fjordbyen |url=https://www.oslo.kommune.no/slik-bygger-vi-oslo/fjordbyen/bjorvika/ |access-date=2024-04-06 |website=Oslo kommune |language=no}}</ref> [[Nydalen]]<ref>{{Cite web |date=2023-01-14 |title=Det er Nydalens siste ubebygde tomt. Kravene om park er blitt hørt, men blir den stor nok? |url=https://www.aftenposten.no/oslo/i/69B9jr/slik-planlegges-den-siste-store-utbyggingen-i-nydalen |access-date=2024-04-06 |website=www.aftenposten.no |language=nb}}</ref> and [[Sinsen]], this is increasing the density in and arond [[Ring 2]] and [[Ring 3]]. The [[Fornebu Line|Fornebu line]] on the metro is under construction as of 2024, and further subway lines crossing the inner city are being planned.<ref>{{Cite web |date=2017-09-27 |title=Fornebubanen - Slik bygger vi Oslo |url=https://www.oslo.kommune.no/slik-bygger-vi-oslo/fornebubanen/ |access-date=2024-04-06 |website=Oslo kommune |language=no}}</ref>

<gallery mode="packed" heights="140">
File:Medieval Oslo map.jpg|Map of medieval Oslo,<br />by [[Amund Helland]]
File:Harbour of Christiania (JW Edy plate 50).jpg|1800–1820: Port of Christiania,<br />by [[John William Edy]]
File:Bridge, at Christiania (JW Edy plate 52).jpg|1800–1820: the old [[Vaterland, Norway|Vaterland]] Bridge,<br />by John William Edy
File:Christiania Norway in 1814 by MK Tholstrup.jpg|1814: Christiania seen from [[Ekeberg]],<br />by M. K. Tholstrup
File:Homannsbyen.jpg|1867: [[Homansbyen]],<br />by [[Georg Andreas Bull]]
File:Hjula Veveri JWC.240.jpg|1867: [[Hjula Veveri]] besides [[Akerselva]],<br />by [[Carl Baagøe]]
File:Karl Johan 1880s.jpeg|1890s: [[Karl Johans gate]]
File:0133. Christiania, Nationalteatret, 1897 - NB bldsa AL0133 2.jpg|1897: the [[Christiania Theatre]]
File:2 Universitetet. Kristiania - no-nb digifoto 20151127 00220 bldsa PK09950 (cropped).jpg|1800s–1900s: the [[University of Oslo|University of Kristiania]]
File:Stortorvet 7, Stortorvet 8 med Kaffistova, Karl Johans gate 15, 1926, Anders Beer Wilse, Oslo Museum, OB.Y2962.jpg|1926: [[Karl Johans gate]] 15
File:Oslo-oslo-sporveier-sl-2-601737.jpg|1971: tram ([[Frogner Line]]) at Frognerveien
</gallery>