This month on Capitol Hill, congressional staffers can don a VR headset and take part in the start of an atomic holocaust. Nuclear Biscuit simulates an intercontinental ballistic missile strike on the United States and gives users 15 minutes to make a presidential choice: Will they push the button for a retaliatory strike and kill tens of millions of people?

We’re on high nuclear alert this month. North Korea has escalated its missile tests, with apparent advances in its nuclear and ballistic capabilities. Heightened tensions around Ukraine have raised the prospect that Russia could place nuclear weapons close to the U.S. coastline, while the struggle over Taiwan has increased the chances of nuclear conflict with China. Meanwhile, Swedish authorities scrambled after drones circled three of the country’s nuclear power plants.

These threats pose a risk not only of a deliberate nuclear attack, but of a hair-trigger response to a false alarm that generates a bloodbath no one wanted. In the past, the world has experienced a number of very high-profile (and sometimes dangerous) false alarms. Here are some of the most ludicrous, terrifying and near-deadly.

A game of chicken

At 4:19 p.m. on March 11, 1958, children Helen and Frances Greggs were playing with their cousin in the yard of their South Carolina home when a U.S. Air Force B-47E bomber accidentally dropped its payload — a 7,600-pound nuclear weapon — onto the girls’ playhouse.

The device had been “safed,” meaning the radioactive part was on a different plane. Nevertheless, the devices high-explosive trigger leveled the Greggs’ home. The release occurred when the plane’s bombardier was trying to secure the payload: Crouched next to the bomb, he stood up and accidentally used the overhead emergency release lever as a handrail to steady himself. No one was killed, bar the chickens vaporized in the farmyard. The accident led to a swift revision of regulations for locking pins when weaponry was being transported.

Blood moon

On Oct. 5, 1960, NORAD, the U.S. nuclear command center, indicated that its early warning radar in Thule, Greenland, had detected a Soviet atomic attack on the West. It was reporting a 99.9 percent chance that a salvo of ICBMs was crossing the Atlantic.

Land-based U.S. missiles are kept ready to launch a quick counterattack against the aggressor. But in this case, the culprit was not the Russians or the Chinese.

It was the moon. Innocently rising in the Norwegian sky, it had reflected radar waves back at the monitoring station in Thule. Scientists have since modified detection equipment to distinguish between missiles and natural satellites.