Scores of anti-nuclear activists marked the 69th anniversary of the Hiroshima and Nagasaki bombings by riding bikes in a seven-mile loop around Washington to show the blast radius of a nuclear weapon.
The 100 or so riders, in a protest called "Bike Around the Bomb," passed the White House, the Capitol and monuments on the National Mall. They ended at a bar.
Global Zero, a group that seeks elimination of all nuclear weapons, organized the ride and related events Saturday in Berlin, London, Islamabad and New Delhi.
"The goal is to remember Hiroshima and Nagasaki, and remember the only way for this to never happen again is to eliminate all nuclear weapons," said John-Michael Donahue, a U.S. organizer for Global Zero. "We need people to actually do something about it."
The twin bombings in 1945 killed more than 150,000 people immediately, with many more casualties later from burns and radiation sickness. But the bombs led Japanese leaders to quickly surrender, ending World War II.
Riders said Saturday they hoped to push President Obama to do more to achieve deeper nuclear disarmament.
"There has been a lack of political leadership on this issue," said Erin Finucane, Global Zero's campaign director.
Former Assistant Secretary of Defense Lawrence J. Korb urged the activists to pressure Obama to eliminate all nuclear weapons.
"He's got two years left," Korb said. "He understands, he's articulate. … This would be a great legacy for him."
The United States and Russia hold the largest stockpiles of nuclear weapons.
In 2011, the two countries implemented the New START treaty, designed to limit the number of deployed nuclear warheads to 1,550 by February 2018.
But U.S. relations with Russia are at a low ebb due to the conflict in Ukraine, and further cuts are unlikely anytime soon.
Some participants say the issue is pressing.
"I think the world is gravely at threat from nuclear weapons and the American public, especially younger people who didn't grow up during the Cold War, don't understand that there are so many nuclear weapons," said Catherine Thomasson, executive director of Physicians for Social Responsibility, a nonprofit working to prevent nuclear proliferation.
Some riders came for the exercise, or the perks.
"They were out there recruiting for this and a girl gave me a flier that said 'free drink,'" said Ethan Jansen, a participant. "I figured it can't hurt."