NATO consists of 32 countries across North America and Europe.

NATO was formed in 1949 to deter Soviet expansion, prevent European militarism, and encourage political integration.

NATO has only invoked its mutual defense clause once, in the days after the 9/11 attacks.

Members decide to what extent they respond to an attack on an ally

The NATO constitution is intentionally vague about what exactly is required from its members. Explore the historical debates and learn more about common misconceptions about NATO’s common defense clause.

Decisions at NATO are by consensus and must be unanimous

There are two strategic commands in NATO: one in Europe (Supreme Allied Headquarters Command Europe) and another in Norfolk, Virginia (Allied Command Transformation). The alliance is headed by both a military officer and a civilian leader.

Watch the historic treaty signing that established NATO in 1949

NATO was created with the signing of the North Atlantic Treaty on April 4, 1949, in Washington, DC. The clip embedded in the webpage includes a newsreel with an excerpt from US President Harry Truman’s speech celebrating the historic day.

How NATO responded to 9/11

The collective defense clause of the NATO constitution has only been invoked one time: after the 9/11 terrorist attacks against the United States. This video explores the immediate actions NATO took to respond to the attacks to support the United States. These firsthand clips from 2001 give a sense of the magnitude of the moment and the difficult decisions facing NATO leaders at the time.

As of 2025, every NATO member spent at least 2% of GDP on defense, a target the alliance had been pushing toward for over a decade.

The treaty's Article 5 requires mutual defense, but not necessarily military action.

The alliance operates under a "flexible response" doctrine—that is, proportionality

NATO countries' main deterrent against aggression is their ability to respond with nuclear weapons. This video from "The Infographics Show" outlines the purpose of this nuclear arsenal, NATO’s strategy to prevent attacks, and its plans in the event of escalation toward nuclear war.

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.

Tensions between the US and European NATO allies

The Associated Press article discusses US Defense Secretary Pete Hegseth's assertion in February of 2025 that restoring Ukraine's prewar borders or NATO membership for the country are both unrealistic. This represented a large rift between the United States and its other NATO allies, prompting concern about America’s commitment to the future of the alliance.

NATO's Article 5 has been invoked once—after 9/11

The article was invoked the day after the attacks and launched a series of NATO campaigns to fight global terrorism. This page includes excerpts from a speech by then-NATO Secretary General Jens Stoltenberg about the attacks and the organization’s response.

National Hockey League, explained

Founded in 1917, the NHL started with four Canadian teams and now spans 32 franchises across North America. Its iconic Stanley Cup, first awarded in 1893, remains a unique prize, with winners' names hand-engraved each year. The league generates billions in annual revenue, aided by key expansions, lucrative TV deals, and global fan engagement. While player safety and labor disputes have posed challenges, the NHL remains a cornerstone of professional sports, offering an 82-game season culminating in the fiercely contested Stanley Cup Final.

There are 32 teams in the NHL

Click a team to see their current record and opponent for the day; read the latest news, including injuries; view the remaining schedule; scan where the team is in the divisional standings; review the current roster; skim all the player and team stats; and watch the latest video highlights.

NATO leads cyber war games in Estonia

Estonia is host to one of the world’s largest annual interactive cybersecurity drills. Russia is always considered the main threat, but this year, the war in Ukraine has only added to the stakes.

NATO condemned Russia's 2022 invasion of Ukraine

While Ukraine is not a member, NATO responded forcefully to the Russian invasion of the country in 2022. This page from the NATO website offers answers to frequently asked questions about NATO’s response to the invasion, specifically on how NATO is aiding Ukraine.

Germany is pursuing its most significant military buildup since WWII.

193 nations are members of the United Nations

The UN's Member States webpage provides an alphabetical list of all 193 member countries, along with the exact dates they were admitted. Take a look at how the UN has expanded over time and understand each nation's place in the global organization.

The 2026 FIFA World Cup will feature 48 teams, making it the largest field in World Cup history.

The 1955 Warsaw Pact was the Soviet Union’s answer to NATO

The pact included Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, Romania, and the USSR. The pact established collective security and a joint military command between the member countries.

The Cold War (1947-1991) prompted the birth of NATO and the Soviet Warsaw Pact

The geopolitical rivalry between the United States and Soviet Union was considered “cold" because the two countries never directly engaged in military combat during the time period. This page from the Kennedy Presidential Library outlines the causes and major events of the early Cold War.

General Jennie Carignan was the first woman to lead a NATO mission

"NATO Through Time" is a podcast exploring NATO's history and its impact on today's world. This episode features General Jennie Carignan, Canada's top military leader, as she shares insights from her NATO missions in Bosnia, Afghanistan, and Iraq.

Explore the countries with a federal system—and see how they work

This resource from the Forum of Federations catalogs the world's federal countries. It provides background information on each, including the emergence of federalism, the division of power, and the practical interaction between national and regional governments.

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.

The National Security Council advises the president on foreign policy and national defense

Created in 1947, the NSC coordinates military, diplomatic, and intelligence policy matters. Chaired by the president, it includes key Cabinet officials and senior advisers who shape American responses to global crises and security threats.

The Big Ten is the oldest Division I collegiate athletic conference in the US

Established in 1896 with seven members, the Big Ten has expanded far beyond its Midwestern roots. As of 2024, it includes 18 schools—stretching coast to coast from Rutgers in New Jersey to UCLA in California.

The Arab League has 22 members and very little enforcement power

It was founded in Cairo in 1945 and spans 22 nations across the Middle East and North Africa, ostensibly to coordinate policy on economics, culture, and defense. Its charter says any resolution only binds states that voted for them, rendering most of them toothless.

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 National Guard serves both state governors and presidents

Roughly 430,000 trained military personnel act as a strategic reserve for the US military, deployed domestically during natural disasters or unrest as well as overseas. It consists of the Army National Guard and the Air National Guard, overseen at the federal level by the National Guard Bureau.

The WNBA includes 13 teams

Many teams share markets with an NBA team, and some share arenas; however, seven are independently owned. The WNBA will expand into Canada in 2026.

Wartime conferences exposed cracks in the US–Soviet alliance

At the Tehran, Yalta and Potsdam Conferences, Allied leaders coordinated WWII strategy—but deep disagreements over postwar Europe foreshadowed the Cold War. The USSR’s push for influence in Eastern Europe clashed with US and British calls for self-determination.

Explore over a century of US-Canadian relations.

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.

The 1941 Atlantic Charter was a World War II alliance and model for the UN

The Atlantic Charter was a pivotal 1941 agreement between Franklin D. Roosevelt and Winston Churchill, outlining shared goals for a post-World War II world rooted in freedom and self-determination. These ideals later inspired the founding principles of the United Nations.

There are 32 teams in the NFL

Click a team's name to see their current record and opponent for the day; read the latest news, including injuries; view the remaining schedule; find out where the team is in the standings; discover the current roster; explore all player and team stats; and watch the latest video highlights.

Explore a map of data centers worldwide, numbering over 12,250 as of August 2026, with over 4,500 in the US.

Why is the Black Sea region strategically important?

This commentary is the first in a series of essays that examine the strategic significance of the Black Sea region to the US and NATO.

A 1983 NATO war simulation provoked the Soviets to prepare for war

The "SNAFU" podcast, hosted by actor and comedian Ed Helms, explores some of the biggest blunders in history. Season one focuses on the 1983 NATO Able Archer military exercise, a war game that simulated nuclear attacks on the Soviet Union. The USSR mistook the exercise for a genuine threat and prepared its forces for war. Helms recounts this almost catastrophic event in world history with his signature humor.

See an animated map of the entire Cold War.

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

The Marshall Plan aimed to rebuild Europe and limit Soviet influence

Launched in 1948, the Marshall Plan provided over $12B (roughly $150B today) in US aid to help rebuild Western Europe. While framed as economic recovery, it also served as a Cold War tool—tying countries to the US and excluding the Soviet bloc.

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.

Nearly half of the discretionary funding in the US is allocated to national defense.

Federal systems are a minority among the United Nations' 193 members

Of the United Nations' 193 member countries, roughly two dozen use a federal system, dividing power constitutionally between national and subnational governments. This group includes the United States, India, Canada, Germany, and more. The video walks through examples of how these states operate.

The NBA consists of 30 teams and 450 players

The teams are divided into two conferences, the Eastern and Western, each playing 82 games from mid-October to mid-April. Conference champions meet in the NBA Finals each year in late May or June to crown a league champion.

The Concert of Europe was an earlier attempt to manage great power relations through shared rules

After the Napoleonic wars, European powers established a system of regular consultation to manage conflicts and maintain the balance of power. It offered relative stability for nearly a century before deteriorating.

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

This interactive tool from the National Constitution Center allows you to compare constitutional rights globally, highlighting which countries have adopted protections similar to those in the US Constitution—and how shared principles manifest in different legal forms around the world.

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.

The world rapidly decolonized after World War II, with roughly a hundred new countries emerging between 1945 and 1989.

Decolonization isn't complete, as nearly 2 million people were living in UN-designated non-self-governing territories as of 2023.

Explore a map of Medieval Europe, which was a patchwork of hundreds of competing states.