STOCKHOLM/HELSINKI (Reuters) - For a city of just 600,000 people on the northeast periphery of Europe, Helsinki has played an outsized role in the fraught relationship between its giant neighbor Russia and the West.

FILE PHOTO: Finlandia Hall, which will serve as a media centre during the meeting of U.S. President Donald Trump and Russian President Vladimir Putin on July 16, is pictured in Helsinki, Finland July 4, 2018. LEHTIKUVA/Mikko Stig/via REUTERS/File Photo

Throughout the 1945-90 Cold War, neutral Finland navigated a precarious but pragmatic course between East and West, finding middle ground that made the capital Helsinki a hotspot for superpower talks between the Soviet Union and United States. The Soviet Union’s 1991 break-up and Finland’s 1995 entry into the European Union ushered Helsinki fully into the Western orbit.

But Finland has kept acting as a bridge for diplomacy and the July 16 summit between U.S. President Donald Trump and Russian President Vladimir Putin in its capital will be the latest installment, with East-West relations tenser than at any time since the Cold War.

Below are some milestones in Helsinki’s diplomatic history.

BALANCING ACT

Ruled by Sweden for centuries, Finland fell under the thumb of Tsarist Russia in an early 19th-century war. It emerged only after the 1917 Russian Revolution, which triggered a year of civil war followed by a declaration as an independent republic.

But the Soviet Union continued to harbor designs on Finland, leading to the 1939-40 “Winter War” in which the country lost some 10 percent of its territory bordering Russia.

Under delicate post-war treaties, Helsinki adopted a policy of accommodation with Moscow while remaining strictly neutral, avoiding membership in either the Soviet-led Warsaw Pact or NATO. Its stance became known as “Finlandisation”, whereby a small state refrains from challenging the policies of a powerful neighbor in exchange for keeping a measure of independence.

While “Finlandisation” became a pejorative word in West European politics, it also made Helsinki a favored venue for negotiating East-West detente after decades of nuclear-edged confrontation.

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HELSINKI ACCORDS

The landmark Helsinki Accords were sealed there in 1975. The deal declared the inviolability of post-war borders in Europe in which eastern states occupied by the Red Army in the defeat of Nazism became Soviet satellites, divided by an “Iron Curtain” border from western states allied with the United States.

It was seen as a diplomatic coup for Soviet leader Leonid Brezhnev. But the Accords also enshrined guarantees on human rights that over time would be used by dissidents in the Soviet bloc and Western powers to pressure Moscow to ease repression.

SOVIET END-GAME

Soviet strength seemed unassailable in the 1970s while the United States grappled with the fallout of the Vietnam War and recession triggered by an Arab oil embargo, but the tables had turned by the time of the next Helsinki summit in 1990.

When reformist Soviet leader Mikhail Gorbachev sat down for talks with U.S. President George H.W. Bush, popular uprisings had toppled Moscow-backed Communist regimes in Eastern Europe.

Iraq’s invasion of Kuwait and the looming U.S.-led counter-attack formed the centerpiece of their talks and the Soviet Union ended up largely supporting the 1991 Gulf War in a stunning break with Cold War tradition.

Gorbachev was soon out of power after an abortive hardline coup in August 1991 that broke up the sclerotic Soviet Union.

BILL AND BORIS

Superpower summitry returned to Helsinki in 1997, between U.S. President Bill Clinton and Russian President Boris Yeltsin, held against a backdrop of NATO plans to admit east European ex-satellites of Moscow into the alliance.

With Russia in disarray amid its tumultuous transition to capitalism, it could do little but protest at NATO expansion into its former sphere of influence, now all Westernized democracies. Superpower tensions frayed anew in ensuing years.

There have been no more U.S.-Russian summits in Helsinki until now but it has continued to host lower-level gatherings.

“Finland is seen as an easy place to arrange meetings in a relatively peaceful place, a bit apart, and there is the symbolic significance too,” said Mika Aaltola, a Finnish Institute of International Affairs analyst.

“Finland is (no longer) neutral, it is tied to the West. But its way of handling foreign policy has made it an acceptable place for this kind of summit.”