Gressholmen Airport

Heggholmen Lighthouse (Norwegian: Heggholmen fyr) is a coastal lighthouse located in the Oslofjord, in the municipality of Oslo, Norway. It was established in 1827, and automated in 1972. The lighthouse was listed as a protected site in 1998.

Gressholmen is an islet located in the Oslofjord, just south of central Oslo. Administratively it belongs to the borough of Gamle Oslo. Gressholmen airport was for the years 1927 through 1939 the location of the main airport for Oslo, until the construction of Fornebu airport. The airport was only for seaplanes. The ramp with rail tracks and the hangar are reused for boat storage and maintenance. There is railway point with the big track gauge. The island is easily accessible from Oslo with the local ferries. The access point is on the North side. A big part of the island is a nature reserve.

Lindøya is a small island located in the Oslofjord, just south of central Oslo. Administratively it belongs to the borough of Gamle Oslo. In 1920, Lindøya was the Oslo base for the pioneer Norwegian airline, Det Norske Luftfartrederi, and its seaplanes. The operation only lasted until the autumn of 1920. When regular seaplane routes were again established in 1927, the operation was moved to neighboring Gressholmen.

Langøyene is an island in Bunnefjorden in the inner part of Oslofjord, in the municipitality of Nesodden in Akershus, Norway. It is owned by the municipality of Oslo. Langøyene were originally two islands, Nordre Langøy and Søndre Langøy. The islands were bought by the municipitality of Kristiania in 1902, and the strait between the two islands has been filled with garbage deposits.

The Oslo Tunnel (Norwegian: Oslotunnelen) is a 3,632-metre (2.257 mi), double-track, railway tunnel which runs between Olav Kyrres plass and Oslo Central Station (Oslo S) in Oslo, Norway. The tunnel constitutes the easternmost section of the Drammen Line and runs below the central business district of Oslo. It features the four-track Nationaltheatret Station, Norway's second-busiest railway station, where the Oslo Tunnels lies directly beneath the Common Tunnel of the Oslo Metro. At Frogner, the Elisenberg Station was built, but has never been used. The tunnel is the busiest section of railway line in Norway and serves all west-bound trains from Oslo, including many services of the Oslo Commuter Rail and the Airport Express Train. Traditionally, Oslo had two stations, the larger Oslo East Station (or Oslo Ø, located at the spot of the current Oslo S) and Oslo West Station (Oslo V), which served the Drammen Line. This caused a physical barrier between the two parts of the railway network, only connected by the Oslo Port Line which ran partly in city streets. Formal planning of a central station and a tunnel connecting the Drammen Line to Oslo Ø started in 1938, and the final plans were approved in 1968. The Oslo Tunnel opened on 1 June 1980, and made it possible to close Oslo V in 1989. Nationaltheatret saw a major upgrade in 1999, when it was expanded to four tracks, and from 2008 to 2010, the tunnel saw a major technical upgrade. There are plans to build a second tunnel to increase train capacity west of Oslo.

The National Internment Camp for Women in Hovedøya (Norwegian: Statens interneringsleir for kvinner, Hovedøya) was Norway's largest internment camp for women, located on the island of Hovedøya in Oslo. It was used to detain women who had been accused of having romantic or sexual liaisons with German soldiers during World War II.

Bleikøya is an island in the inner part of Oslofjord, in the municipitality of Oslo. It is located between Hovedøya and Sjursøya. From the late 19th century, a sanatorium for children suffering from scrofula was located on the island.In 2008 the Bleikøya Nature Reserve was established on the northeastern part of Bleikøya, including the islet Bleikøykalven.

Nakholmen (also spelled Nakkholmen) is an uninhabited island in the inner part of Oslofjord, in the municipitality of Oslo. It is located west of Lindøya and southeast of Bygdøy. The island has more than 180 weekend cottages.

Hovedøya Abbey (Hovedøya kloster) was a medieval era Cistercian monastery on the island of Hovedøya in Oslofjord outside of Oslo, Norway.

Tjuvholmen skulpturpark is a sculpture park in the Tjuvholmen neighborhood of Frogner borough in Oslo, Norway. It is close to Aker Brygge.

Hovedøya is one of several small islands off the coast of Oslo, Norway in the Oslofjord. The island is quite small, no more than 800 metres across in any direction, the total area is 0,4 square kilometre. It is well known for its lush and green nature, with a wide variety of trees, bushes and flowers. For many, many years there was a military base on the island.

Tjuvholmen is a neighborhood in the borough Majorstuen in Oslo, Norway. It is located on a peninsula sticking out from Aker Brygge into the Oslofjord. It is located east of Filipstad and south of Vika. At the tip of the peninsula, next to the sculpture park, is an outdoor bathing area. The water leads out to the Inner Oslofjord. The area was bought by the shipyard Akers Mekaniske Verksted in the mid 19th century, who planned to build a drydock there. Instead, it was bought by the municipality in 1914, and transferred to the port authority in 1919. They built docks and artificial land, increasing the area from 5 to 33 hectares (12 to 82 acres). From the 1960s, Fred. Olsen & Co. rented the docks, and from 1971 Nylands Mekaniske Verkstad had a shipyard on the spot. Since 1982, the area has been used for office space, terminals, and warehouses. The Norwegian National Academy of Ballet was located there. Since 2005, the area has been sold to private developers, who are conducting an urban renewal with housing. The area has about 1,200 apartments since 2012. It is part of the Fjord City urban renewal program. This program has seen the opening of several art galleries, amongst them the Astrup Fearnley Museum of Modern Art and the Gallery Haaken. Tjuvholmen skulpturpark, next to the museum, was created by Renzo Piano.