Germans celebrated through the night as they welcomed the 25th anniversary of the reunification of the former East and West German states on Saturday.
The highlight of the festivities nationwide is a three-day party in Frankfurt which features an official ceremony in the old Opera House on Saturday at which President Joachim Gauck is due to speak and which is to feature Chancellor Angela Merkel among its 1,500 guests.
The main speech to mark 25 years of German unity is to be delivered by the event's host, the state premier of Hesse, of which Frankfurt is the largest city, Volker Bouffier.
Fifty rights activists from the former communist East German Democratic Republic (GDR) have been placed in the front row for the event, among them Vera Lengsfeld, Marianne Birthler and Freya Klier.
The state's coalition government of center-right Christian Democrats and Greens has also invited 30 refugees.
The premiers of most federal states, former foreign minister Hans-Dietrich Genscher, the South Korean Unification Minister Hong Yong Pyo and European Commission President Jean-Claude Juncker are also expected.
Ahead of the celebrations, Juncker said: "The images of German reunification are not just nice pictures for history books, they are true symbols of our European identity.
"They show what people and politics can achieve if they overcome national walls, fences and barriers.
"The images of reunification remain powerful because they remind us what we can accomplish if we think and act beyond the borders on maps and in minds, for a Europe of peace and freedom, of fairness and prosperity."
The main architects of German unity, former German chancellor Helmut Kohl and former Soviet president Mikhail Gorbachev, have said they cannot attend for health reasons.
Saturday is scheduled to start with an ecumenical service in Frankfurt Cathedral at 0800 GMT.
Before that, Bouffier and his wife plan to welcome dignitaries from Germany's constitutional bodies to register in the so-called Golden Book at St Paul's church, a historically significant location where the first freely elected parliament in Germany was held in 1849.
At 1230 GMT, Bouffier, who is currently president of Germany's upper house of parliament, the Bundesrat, symbolically hands on the rotating presidency to the state of Saxony, represented by Premier Stanislaw Tillich.
The national celebrations for German Unity Day on October 3 are traditionally hosted by the state that holds the Bundesrat presidency, meaning next year they will move to Saxony.
The celebrations in Frankfurt began on Friday afternoon and are scheduled to last until Sunday evening, by which time up to 1.5 million people from all over Germany are expected to have attended over 300 events under the motto "Overcoming Borders."
On Saturday evening, visitors will be treated to a light show in which 25 bridges - one for each year of unity - are illuminated along Frankfurt's river Main.
Hesse plans to spend 3.5 million euros (3.9 million dollars) on the festivities, of which the city of Frankfurt's contribution is 1.3 million euros.
It was not all party mood, however, as a group of 1,000 leftist demonstrators marched through the city center on Friday to protest the celebrations, calling instead for all borders to be torn down and for Germany to cease to exist.
The demonstrators said there was nothing to celebrate. "What you are celebrating is ostracism, poverty and partition," they said. They criticized Germany's arms exports, the government's planned toughening of the asylum law and demanded "Never again Germany."
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