Helsinki was established as a trading town by King Gustav I of Sweden in 1550 as the town of Helsingfors, which he intended to be a rival to the Hanseatic city of Reval (today known as Tallinn). Little came of the plans as Helsinki remained a tiny town plagued by poverty, wars, and diseases. The plague of 1710 killed the greater part of the inhabitants of Helsinki. The construction of the naval fortress Sveaborg (In Finnish Viapori, today also Suomenlinna) in the 18th century helped improve Helsinki's status, but it was not until Russia defeated Sweden in the Finnish War and annexed Finland as the autonomous Grand Duchy of Finland in 1809 that the town began to develop into a substantial city.
Czar Alexander I of Russia moved the Finnish capital from Turku to Helsinki to reduce Swedish influence in Finland. The Royal Academy of Turku, back then the country's only university, was relocated to Helsinki in 1827 and eventually became the modern University of Helsinki. The move consolidated the city's new role and helped set it on the path of continuous growth. This transformation is highly apparent in the downtown core, which was rebuilt in neoclassical style to resemble St. Petersburg. As elsewhere, technological advancements such as railroads and industrialization were key factors behind the city's growth.
Helsinki is spread across a number of bays and peninsulas and over a number of islands. The inner city area occupies a southern peninsula, which is rarely referred to by its actual name Vironniemi. Population density in certain parts of Helsinki's inner city area is very high, reaching 16,494 inhabitants per square kilometre (42,720 /sq mi) in the district of Kallio, but as a whole Helsinki's population density of 3,050 per square kilometre ranks it as quite sparsely populated in comparison to other European capital cities. Much of Helsinki outside the inner city area consists of postwar suburbs separated from each other by patches of forest. A narrow, ten-kilometre-long (6 mi) Helsinki Central Park that stretches from the inner city to the northern border of Helsinki is an important recreational area for residents.
Major islands in Helsinki include Seurasaari, Lauttasaari and Korkeasaari – the latter being the site of the country's biggest zoo. Other significant islands are the fortress island of Suomenlinna (Sveaborg) and the military island of Santahamina. Pihlajasaari island is a favourite summer spot for gay men and naturists, very much comparable to Fire Island off New York City.
Carl Ludvig Engel (1778–1840) was appointed to design a new city centre all on his own. He designed several neoclassical buildings in Helsinki. The focal point of Engel's city plan is the Senate Square. It is surrounded by the Government Palace (to the east), the main building of the University (to the west), and (to the north) the enormous Cathedral, which was finished in 1852, twelve years after C. L. Engel's death. Subsequently, Engel's neoclassical plan stimulated the epithet, The White City Of The North. Helsinki is, however, perhaps even more famous for its numerous Art Nouveau (Jugend in Finnish) buildings, designed in the early 1900s and strongly influenced by the Kalevala, which is a very popular theme in the national romantic art of that era. Helsinki's Art Nouveau style is also featured in large residential areas such as Katajanokka and Ullanlinna. The master of the Finnish Art Nouveau was Eliel Saarinen (1873–1950), whose architectural masterpiece was the Helsinki central railway station.
Helsinki also features several buildings by the world-renowned Finnish architect Alvar Aalto (1898–1976), recognized as one of the pioneers of architectural functionalism. However, some of his works, such as the headquarters of the paper company Stora Enso and the concert venue, Finlandia Hall, have been subject to divided opinions from the citizens.
Renowned functionalist buildings in Helsinki by other architects include the Olympic Stadium, the Tennis Palace, the Rowing Stadium, the Swimming Stadium, the Velodrome, the Glass Palace, the Exhibition Hall (now Töölö Sports Hall) and Helsinki-Malmi Airport. The sports venues were built to serve the 1940 Helsinki Olympic Games; the games were initially cancelled due to the Second World War, but the venues eventually got to fulfill their purpose in the 1952 Olympic Games. Many of them are listed by DoCoMoMo as significant examples of modern architecture. The Olympic Stadium and Helsinki-Malmi Airport are in addition catalogued by the National Board of Antiquities as cultural-historical environments of national significance.
As a historical footnote, Helsinki's neoclassical buildings were often used as a backdrop for scenes set to take place in the Soviet Union in many Cold War era Hollywood movies, when filming in the USSR was not possible. Some of the more notable ones are The Kremlin Letter (1970), Reds (1981) and Gorky Park (1983). Because some streetscapes were reminiscent of Leningrad's and Moscow's old buildings, they too were used in movie productions—much to some residents' dismay. At the same time the government secretly instructed Finnish officials not to extend assistance to such film projects.
The Helsinki metropolitan area generates approximately one third of Finland's GDP. GDP per capita is roughly 1.3 times the national average.
The metropolitan area's gross value added per capita is 200% of the mean of 27 European metropolitan areas, equalling those of Stockholm or Paris. The gross value added annual growth has been around 4%.
83 of the 100 largest Finnish companies are headquartered in Greater Helsinki. Two-thirds of the 200 highest-paid Finnish executives live in Greater Helsinki and 42% in Helsinki. The average income of the top 50 earners was 1.65 million euro.
The tap water is of excellent quality and it is supplied by 120 km (75 mi) long Päijänne Water Tunnel, one of the world's longest continuous rock tunnels. Bottled Helsinki tap water is even sold to countries such as Saudi Arabia.
Helsinki has 190 comprehensive schools, 41 upper secondary schools and 15 vocational institutes. Half of the 41 upper secondary schools are private or state-owned, the other half municipal. Higher level education is given in eight universities (see the section "Universities" below) and four polytechnics.
Helsinki has a long tradition of sports: the city gained much of its initial international recognition during the 1952 Summer Olympics, and the city has since then been very open to arranging sporting events, for example the first World Championships in Athletics 1983 and 2005, and European Championships in Athletics 1971, 1994 and 2012 etc. Helsinki hosts fairly successful local teams in both of the most popular team sports in Finland, football, ice hockey and synchronized skating. Helsinki houses Helsingin Jalkapalloklubi (HJK), Finland's largest and most successful football club. Helsinki's track and field club Helsingin Kisa-Veikot is also pretty dominant in Finland. Ice Hockey is a sport of passion for many Helsinki residents, who usually take a stance for either of the local clubs IFK Helsingfors (HIFK) or Jokerit. HIFK, with 14 Finnish championships titles, also plays in the highest bandy division, so does Botnia -69. The Olympic stadium hosted the 1st ever Bandy World Championships in 1957.
Public transportation is generally a hotly debated subject in the local politics of Helsinki. In Helsinki metropolitan area, public transportation is managed under Helsinki Region Transport, the metropolitan area transportation authority. The diverse public transport system consists of trams, commuter rail, the subway, bus lines and two ferry lines.
Today, Helsinki is the only city in Finland to have trams or subway trains. There used to be two other cities in Finland with trams: Turku and Viipuri (Vyborg, now in Russia), but both have since abandoned trams. The Helsinki Metro, opened in the year 1982, is the only subway system in Finland. In 2006, the construction of the long debated extension of the subway system west into Espoo was approved, and serious debate about an eastern extension into Sipoo has taken place.
The possibility of a Helsinki to Tallinn Tunnel is currently being researched. The rail tunnel would connect Helsinki to the Estonian capital Tallinn, further linking Helsinki to the rest of continental Europe by Rail Baltica.