Germany is marking the 75th anniversary of the most famous plot to kill Adolf Hitler, honoring those who resisted the Nazis.
France has taken the bold and unprecedented step of pledging to extend its nuclear deterrent to cover German territory in the case of armed aggression.
Russia is building up its land forces and weapons along the border; German Chancellor Merkel warned Russia not to block Ukrainian ports in the Sea of Azov.
Germany's top security official offered to send federal assistance to the eastern state of Saxony on Tuesday following violence during a far-right protest.
The 42-year-old man was investigated more than a decade ago for extremist ties, including alleged participation in military training in Afghanistan and service in a band of bin Laden's guards. Owing to a lack of concrete evidence, federal prosecutors dropped the investigation in 2007.
Berlin police shot and wounded a 53-year-old Austrian man who yelled and waved a knife inside the cathedral in the center of the German capital.
Germany is still dealing with the legacy of a war the country launched itself: thousands of unexploded bombs hidden beneath one of Europe's busiest cities.
The arrested men had planned to wade through dense crowds of runners and spectators at the Berlin Half Marathon, using knives to slash at anyone in reach.
Today, Germany is the de facto leader of the European Union. Its economy is dependent on the E.U. continuing to function as it has since the late 1990s.