Geoff Brumfiel

We look at what we learned after the second summit between President Trump and Kim Jong Un ended without a deal on denuclearization.

Days before President Trump and Kim Jong Un are to meet in Vietnam, satellite images show no river ice downstream from the key North Korean facility at Yongbyon — a sign the reactor may be running.

This month's summit between President Trump and North Korean leader Kim Jong Un is likely to focus on North Korea's main nuclear weapons center at Yongbyon.

The rocket was supposed to carry a small satellite into orbit. The suspected failure comes just weeks after another launch attempt fell short.

The U.S. and Russia seem increasingly interested in battlefield nuclear weapons. Arms control advocates fear a return to the darkest days of the Cold War.

The Trump administration announced it's producing a new, small nuke to counter Russia's own tactical nuclear weapons. Critics fear the plan could mark the return to the darkest days of the Cold War.

The submarine-launched missile is a smaller variant of an existing weapon. The administration says it's needed to deter Russia.

Iran attempted to launch a rocket carrying a satellite into space. The Trump administration believes the launch was about developing long-range weapons, but analysts say the tech used is too clunky.

The strategy, reminiscent of the Cold War-era Star Wars program, calls for new sensors in space, updated missile interceptors and advanced weapons, including lasers.

Iran says its intentions are peaceful, but the U.S. worries the planned launches are really about developing weapons — specifically, intercontinental ballistic missiles.

Government, academic and industry researchers often depend on each others' work and funding. The partial shutdown is getting in the way of some of that collaboration and research.

A newly released report shows that the United States' CO2 emissions spiked last year. A booming economy and busy transportation sector are to blame.

Here's why the drone tormenting Gatwick's airport remains at large.

New research shared exclusively with NPR suggests that Pyongyang is refining its weapons technology through open scientific research. China leads the way in scientific collaboration with North Korea.

Satellite images reveal tunneling and other construction activity at two sites near the Chinese border that are believed to house long-range missiles that could in theory reach the United States.

Five months after the Singapore summit, North Korea's nuclear program chugs on. "I think right now, we are absolutely stuck," says North Korea expert Sue Mi Terry, a former CIA analyst.

The previously undisclosed base contains networks of tunnels used to hide and fuel mobile missiles. Intelligence agencies believe there are some 20 similar bases scattered throughout North Korea.

The Trump administration is poised to reimpose sanctions on Iran this Monday. Tehran has been abiding by the nuclear deal, but some warn that it could fall apart in the face of renewed sanctions.

The U.S., China and Russia have stepped up efforts to develop hypersonic weapons, which are capable of speeds five times the speed of sound and could change the face of warfare.

President Trump says he will pull the U.S. out of a 1987 arms control treaty with Russia. It was a treaty signed by President Reagan designed to reduce the dangers of nuclear war.