The global nuclear arms regime has slowly eroded over the past few decades

Both Russia and the United States have withdrawn from key Cold War-era arms-control pacts. Russia's 2022 invasion of Ukraine marked a turning point, as it suspended its participation in inspections and data-sharing agreements.

See how global nuclear arsenals surged—then shrank—by country since 1945

Worldwide nuclear stockpiles peaked at over 60,000 warheads in the mid‑1980s during the US-Soviet arms race. Today, about nine nations collectively maintain roughly 12,000 warheads, with Russia and the US still holding the majority.

Nearly 90% of the world's 12,187 nuclear warheads are held by Russia and the United States.

South Africa: the only nation to build nuclear weapons—and dismantle them by choice

During the 1980s, South Africa secretly built six uranium "gun‑type" nuclear bombs. In the 1990s, the government dismantled all its weapons and joined the NPT in 1991—the only country to fully reverse its nuclear program.

Chernobyl's remaining reactors kept running for 14 years after the explosion

Due to energy shortages in Ukraine, Chernobyl's other undamaged reactors continued operating for years. Units 1 and 2 operated until 1996 and 1991, respectively, while Reactor 3 remained online until December 15, 2000, when Ukraine finally shut down the plant.

Ukraine became independent after the Soviet Union's collapse

Ukraine declared independence on Aug. 24, 1991, following the dissolution of the Soviet Union. In a national referendum, over 90% of Ukrainians approved independence, establishing a democratic constitution and marking the birth of a modern sovereign state.

Ukraine has received over $300B in Western military and financial aid

Although not a member of NATO, Ukraine has received substantial support from Western nations, primarily the United States and the European Union, totaling more than $300B in military, financial, and humanitarian assistance.

During the Cold War and into the 21st century, US and Soviet/Russian leaders repeatedly agreed to arms control treaties, though strained tensions have led to the expiration of agreements in recent years.

Breaking down Western military weapons in Ukraine

Since the beginning of the Russian invasion of Ukraine in February 2022, Western military aid has helped dictate Ukraine's capability and strategy on the battlefield. From advanced ground-launched missiles to millions of rounds of ammunition, the supplies have been critical for Ukraine but force Western countries to tip-toe around the appearance of direct conflict with Russia. This visual deep-dive breaks down some of the most important military aid to date.

The last remaining US-Russia nuclear arms treaty expired in February 2026

The New START treaty, which capped US and Russian strategic warheads at 1,550 each, expired on Feb. 5, 2026. Without formal limits, fears of a renewed arms race are rising, as both nations could deploy more weapons while follow-on talks continue.

Russia's invasion of Ukraine has destabilized safety and oversight at Chernobyl

Russian forces cut power and disabled monitoring of the decommissioned nuclear power plant in 2022, endangering operators at Chernobyl. In February 2025, a Russian drone struck the confinement structure—part of broader efforts to pressure Ukraine's energy infrastructure—punching a hole in the containment shell.

China doubled its nuclear stockpile between 2020 and 2025, with plans for further expansion.

The Soviet Union’s surprising first atomic test ended the US nuclear monopoly

In 1949, the USSR successfully tested its first atomic bomb—ending the US monopoly on nuclear weapons and sparking an arms race that would define the Cold War.

Four Cold War hawks warn: Nuclear weapons still threaten the world

Despite the Cold War's end, the US and Russia still hold 95% of the world's nuclear weapons—many on hair-trigger alert. In this 2010 documentary, top former officials urge urgent action to reduce and eliminate the threat.

Many countries remained neutral after Russia's invasion of Ukraine

Following Russia's 2022 invasion of Ukraine, few nations outside the West imposed sanctions on Moscow. Major powers such as China, India, Brazil, and Turkey remained neutral, underscoring global divisions over how to confront Russian aggression.

Russia controls about 20% of Ukraine's territory

As of February 2026, Russian forces occupy roughly one-fifth of Ukraine, including Crimea and large parts of the Donetsk, Luhansk, Zaporizhzhia, and Kherson regions, with front lines largely unchanged for months.

The Chernobyl disaster released more radioactive material than the Hiroshima bomb.

Questions about the US' commitment to its allies may have sparked a new nuclear age

Some US allies—from Warsaw to Seoul—are reevaluating their security amid doubts over American nuclear commitment, signaling the possibility they may want to acquire their own weapons.

The Tsar Bomba was the most powerful nuclear weapon ever tested

In 1961, the Soviet Union detonated AN602—known as the Tsar Bomba—the largest nuclear explosion in history. Newly released Russian footage starkly illustrates the unmatched destructive power of this nuclear weapon.

Chernobyl pushed the world to create rapid-alert systems for nuclear accidents

In the aftermath of the disaster, nations adopted new agreements requiring immediate international notification of nuclear accidents. They coordinated emergency assistance—efforts led by the International Atomic Energy Agency to prevent future disasters from being concealed when radiation emergencies occur.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

Prehistoric to present day Ukraine

Recognizing the abundance of information available on the current war between Ukraine and Russia, this video focuses on the history of the region. Encapsulating Ukraine's background, the viewer will gain a better grasp of how the modern state arose from a quilt of different ethnicities, noteworthy conflicts between various groups, and more.

The Chernobyl disaster prompted a sharp decline in public confidence in nuclear power

A Gallup poll from two months after the disaster showed 73% of respondents opposed building a nuclear plant near their homes—up from 45% in 1976. Chernobyl and other nuclear accidents remain in the public consciousness today in debates about nuclear power.

Ukraine's Soviet Republic was tightly bound to Moscow's control

Proclaimed in 1917 and absorbed into the USSR in 1922, the Ukrainian Soviet Socialist Republic was nominally independent yet operated under Moscow's control, with its government and laws directed by the Soviet Communist Party.

Ukraine's pro-Russian President halted an EU deal in 2013, leading to a mass protest movement

In late 2013, President Viktor Yanukovych suspended preparations for a long-negotiated EU association agreement under Russian pressure, signaling a return to Moscow's influence and sparking mass Euromaidan protests across Ukraine.

Finland and Sweden joined NATO after Russia's invasion of Ukraine

In response to Russia's 2022 invasion of Ukraine, Finland and Sweden abandoned decades of military neutrality to join NATO, marking a major shift in Europe's security landscape and expanding the alliance to Russia's borders.

The disaster affected the Soviet Union's credibility at home and abroad

The USSR's secretive, chaotic response to Chernobyl dealt a significant blow to its legitimacy. Public anger over deception, health risks, and propaganda fueled mass protests, strengthened independence movements in Ukraine and Belarus, and convinced many Soviets that the system was failing.

Ukraine came under Russian imperial rule in the late 18th century

After centuries of division among neighboring powers, most of present-day Ukraine was absorbed into the Russian Empire by the late 1700s, marking the beginning of a long period of imperial control and cultural suppression.

Putin claimed the invasion of Ukraine was to demilitarize and 'denazify' the country

In a 5,000-word historical treatise he wrote himself, President Vladimir Putin claimed the move was meant to restore Russia's historic lands. Many Western historians and global leaders described these narratives as false pretexts for aggression.

See what became of Pripyat, the Soviet town built to house Chernobyl's plant workers, a year after the nuclear disaster forced its evacuation.

The origins of Putin's 'Nazism' claim in Ukraine

Ukraine has had a varied history, and is home to a rich diversity of ethnicities, religions, and people. In the time leading up to Russia's attacks on the country, Russian President Vladimir Putin referred to Ukraine as a "Nazi nation", owing to Ukrainian nationalists' acceptance of the invading Nazis as liberators from the Soviet Union in WWII. The history is more complex than that. Read this Smithsonian Magazine article to learn more.

Testing assumptions about the war in Ukraine, one year later

Two years ago, policymakers in Washington made multiple predictions about the course of the war between Russia and Ukraine. One year later this site revisited several common assumptions about the war—for example, that Russia would swiftly defeat Ukraine—and asks several experts if they came true, or not. But things can always change.

Russian forces seized Ukraine's Crimean Peninsula in 2014

Days after Ukraine's 2014 revolution, unmarked Russian troops occupied key sites in Crimea, a Black Sea peninsula with a predominantly Russian-speaking population that had been part of Ukraine since 1954.

Russia's full-scale invasion of Ukraine began on Feb. 24, 2022

Russia launched a massive multifront assault from Belarus, Russia, and Crimea, aiming to seize Kyiv within days. Instead, Ukrainian forces repelled the advance, halting Moscow's plans for a rapid takeover.

A primer on the president's nuclear football

During the Cold War, the United States and the USSR were forced to prepare for a nuclear strike at a moment's notice, leading to a new innovation: the so-called "football" (known as the chemodanchik in Russia), a bag containing nuclear strike plans, authentication codes, and likely a communication device, which attended the country's leader wherever they went. This easy-to-read piece breaks down the history and lore around the high-stakes quirk in nuclear governance.

More than 500,000 people worked to contain Chernobyl's fallout, many with very little radiation protection.

Experts argue that nuclear war is more likely than is commonly believed

The podcast highlights that many of the world's roughly 12,000 nuclear weapons—capable of triggering global collapse and nuclear winter—remain on high alert. Experts warn that this status, combined with limited public awareness, makes nuclear war disturbingly plausible.

Economic stagnation and the arms race pushed the USSR toward collapse

By the 1980s, chronic economic stagnation and soaring military costs forced Gorbachev to launch sweeping reforms—perestroika and glasnost—to revive the Soviet system. Instead, openness fueled independence movements across the republics, accelerating the regime’s rapid downfall.