Trondheim has 12 official twin cities, but we also have close ties with Klaksvik (The Faroe Islands), Upernavik (Greenland), Östersund (Sweden) and Sundsvall (Sweden) through a chain of twin cities.

Darmstadt (Germany)
Twin city since 1968

Darmstadt is situated 30 km south of Frankfurt am Main and has 147.471 inhabitants (2007). Darmstadt has a versatile industrial production base, including machinery, televisions, software and chemicals.

The seat of European space research, it has a well-known technical university founded in 1836, a number of academies and museums. The city is the home of the PEN club. The German Academy of Language and Fiction awards the Georg Büchner-Preis award every year.

Darmstadt was incorporated as a city in 1330, served as the state ruler's city of residence from 1567 and was the capital of Hessen from 1919 to 1945. Around the turn of the previous century the city became the centre for the "Jugend" art nouveau style, championed by the artist colony at Mathildenhöhe. The inner city of Darmstadt has been rebuilt after the destruction in 1944 near the end of the war. Many historic buildings made it unscathed through the war, including the Residential palace (1568-95) and the Russian church (1898-99).
Darmstadt in Wikipedia

Dunfermline (Scotland)
Twin city since 1945

Dunfermline in Great Britain, Scotland, Fife, 20 km north-west of Edinburgh, has 45 462 inhabitants (2006)). The city has a textile industry, dairy production, and coal production in the surrounding area. There are ruins of a castle, and a Benedictine monastery with the graves of Scottish Kings, including Robert Bruce's grave. Andrew Carnegie was born in Dunfermline and donated large gifts to the city.

Dufermline in Wikipedia

Graz (Austria)
Twin city since 1964

Graz is the capital of Steiermark, with 291 574 inhabitants (2009), is situated on both banks of the Mur river, which flows through a wide plain (Grazer Feld) on the south side of the Alps. Graz is the second largest city in Austria and has substantial industries based on a copious supply of hydropower.

Steyr-Daimler-Puch produces mopeds here. Graz has several large breweries, and also has major manufacturers of iron and steel, machines, optical instruments, leather goods, paper, textiles and chemicals.

The city has a university founded in 1586, a technical university, a university for music and the performing arts, and a number of technical schools, museums, theatres and operas. The centre of Graz has been on UNESCO's List of world natural and cultural heritage sites since 1999.
Graz in Wikipedia

Kopavógur (Iceland)
Twin city since 1946

Kopavógur lies on the western coast of Iceland, southwest of Reykjavik. Growing fast, the city now has 30 180  inhabitants (2005). West of the city is the site of the Icelandic president's residence, Bessastadir. The city has a keen focus on culture, and features an art gallery, a library and a museum of natural history.

Kopavógur also has a modern sports centre and one of the best swimming pool facilities in Iceland. There are great opportunities for horse riding, golf, sailing and other outdoor sports.
Kopavogur in Wikipedia

Norrköping (Sweden)
Twin city since 1946.

Norrköping is in eastern Sweden and has around 127 059 inhabitants (2005). Little is left of Norrköping's long traditions in the textile industry. Now the major industries are timber and timber processing and mechanical industries. Northeast of the city lies Kolmården zoo. Situated on the E4 motorway, the city is a transportation centre with an oil port, airport and railways.

The city core is dominated by the urban planning of the 1600s, but only a few buildings from the 1600s and 1700s are still standing. Talk of Norrköping as a city dates all the way back to the 1200s, and it flourished in the 1600s as Sweden's first industrial site and export port for its ironworks. For a period of time it was Sweden's largest city. The city experienced new industrial growth in the 1800s.  

Many of the old industrial plants from the 1800s have been rebuilt into museums and theatres. The city has a new concert and congress centre from 1994.
Norrköping in Wikipedia

Odense (Denmark) 
Twin city since 1946

Odense lies in a central location on the island of Fyn in Denmark. The city has around 158 678 inhabitants (2009), and is an important trade and industry city. It has a substantial mechanical engineering industry producing electro-technological products, agricultural machines and so on. There is also food and beverage production, a textile and clothing industry and paper industry.

A seven km long channel connects Odense with Odense Fjord. The city is an important port with road and railway connections to the rest of Denmark. Beldringe airport lies 10 km north of the city. Odense is the administrative centre for "Fyns amt" (Fyn county administration) and a bishopric seat. It has a university, houses the administration for Denmark's TV2 station and has a number of cultural institutions, including an opera house.
 
Odense is one of the oldest cities in the Nordic countries, mentioned as early as 988, and it became a bishopric in 1020. A number of churches and older buildings from the 1100s and 1200s are well preserved. 

In 2005 there will be bicentennial celebrations of the birth of the author Hans Christian Andersen, who was born in Odense.
Odense in Wikipedia

Petach-Tikva (Israel)
Twin city since 1975

Petach-Tikva lies 11 km east of Tel Aviv and has around 188 900 inhabitants (2007). It was founded in 1878 as the first Jewish settlement in modern-day Palestine. It is a modern city with a versatile industry and cultural activities. Petach Tikva received its status as a city in 1937, and had 22 000 inhabitants when Israel was founded in 1948.

Next to Haifa, Petach Tikva is the most industrialized city in Israel. The city is proud of its good schools and educational opportunities, and has many modern hospitals, including a large hospital for children, and several sports facilities. Petach-Tikva in Wikipedia

Ramallah (the Palestine territories)
Twin city since 2004

Ramallah in the Palestine territories, lying 15 km north of Jerusalem, about 830-900 metres above sea level, has 27 460 inhabitants (2007). It was founded around 1550. Ramallah is the most important centre for industry and service provision for Palestinians in the middle region of the West bank, primarily in the production of foods and chemicals, trade, public services and administration.

A large part of the administration of the Palestinian autonomous area is located in Ramallah, with authority and responsibility for the West Bank, while parallel offices have been established with similar authority for the Gaza strip in Gaza city. The largest and best known university in Palestine is Bir Zeit 10 km outside Ramallah. Yasir Arafat, the former leader and president of the Palestinians, had his headquarters in Ramallah during the last years of his life, and is buried here.
Ramallah in Wikipedia

Split (Croatia)
Twin city since 1956.

Split situated on an isthmus on the Dalmatian coast, has 189 000 inhabitants (2001). A railway centre and busy port, it has a varied industry, including shipyards, and cement, chemical and electro-technical plants, food and beverage industries and fisheries. Known for its beaches and good swimming sites it is also a popular tourist city.

There is also a university (founded in 1974), a large archaeological museum, a city museum, a maritime museum, zoological gardens and an oceanographic institute. It is a Catholic archbishopric. The Roman Emperor Diocletian's palace houses his mausoleum (a church since the 800s) and temple. From around 620 Split grew within the area of the ruins of the Imperial Palace. It belonged to Venice from 1420 to 1797, and to Austria until 1919.

Six km north of present-day Split is the ancient city of Salonae, which was razed by the Slavs in 640 BC. Recently there have been substantial excavations of Emperor Diocletian's vast palace from around 300 BC.
Split in Wikipedia

Tampere (Finland)
Twin city since 1946.

Tampere is the third largest city in Finland, and the largest centre in the Nordic countries that is not on the sea. The city has more than 209 748 inhabitants (2009) and is growing rapidly. At the start of the 1900s Tampere was Finland's largest industrial city, and it continues to be an industrial centre. Research and education, and cooperation between education and industry strongly contribute to maintaining the city's competitiveness.

Tampere was founded by King Gustav III of Sweden in 1779, and has been an industrial pioneer since Finland's first paper mill was founded here in 1783. It has been a free city from 1821. During the civil war in 1918 Tampere was the main headquarters for the "Reds", and in April 1918 it was the theatre for one of the decisive victories for the "White" army.

There are 200 small and large lakes in Tampere, constituting around one fourth of the city's area. Tampere has many natural areas, parks and green areas.
Tampere in Wikipedia

Tiraspol (Capital and administrative centre of the Pridnestrovian Moldavian Republic Transnistria) Twin city since 1987

Tiraspol in Moldova lies on the river Dnestr and has 159.163 inhabitants (2005). It has a river port and food and beverage, textile, glass and furniture industries. Tiraspol was founded in 1795 and from 1929 to 1940 it was the capital of the Moldavian Autonomous Soviet Republic (founded 1924).

After Moldova gained independence in 1991, Soviet-friendly forces on the eastern bank of the Dnestr declared this region of Moldova to be independent with Tiraspol as its capital.
Tiraspol in Wikipedia

Vallejo (USA)
Twin city since 1956

Vallejo, located on San Francisco bay about 55 km north of San Francisco, has rich maritime traditions. It has around 120 000 inhabitants (2004) and for more than 135 years.

Vallejo has been a base for the American navy, which established United States Mare Island Naval Shipyard here, the first naval shipyard on the western seaboard.

Since the base closed in 1996, inhabitants have worked hard to improve their city. Plans call for making Mare Island a major economic centre with jobs, housing, light industry and other amenities. There are also plans to revitalize downtown and waterfront areas with housing, attractions, shops and restaurants. Vallejo is facing an exciting decade.
Vallejo in Wikipedia

Sources: www.trondheim.no - www.kunnskapsforlaget.no - Wikipedia